I know that ubuntu 18.04 LTS needs python 3.6 for doing a lot of its stuff, but I need to run a lot of python 3.7 applications and I don't get that why there is a conflict between them, I had to go over all non-running programs in /usr/bin and change the line #!/usr/bin/python3 to #!/usr/bin/python3.6 and I'm not sure if there are some more files I should change, and I'm worried someday my PC won't boot up 'cause of that :(  Is there a way to make that conflict go away and use only python3 command for everything?  P.S. I did a lot of searching and came up with nothing so if this is a duplicate question I'm sorry  Thank you all in advance :)  Edit:  This is the error log output when I run a system program with python3.7  Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 11, in <module>     from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler   File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 28, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg' Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook     from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>     from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>     import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>     from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 24, in <module>     import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'  Original exception was: Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 11, in <module>     from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler   File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 28, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'   It's also the same if I run an app that needs 3.7 with the 3.6 version.

I run below command on ubuntu 16.4 :  sudo add-apt-repository ppa:noobslab/apps  of below question:    and get below error:  Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 11, in <module>     from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler   File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg' Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook     from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>     from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>     import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>     from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 23, in <module>     import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'  Original exception was: Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 11, in <module>     from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler   File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'   Thanks for help


the alarm doesn't work at the specified time (20 December 2018, 12:10:02)  what is the problem with this code?  Calendar c = Calendar.getInstance(); c.set(Calendar.MONTH,12); c.set(Calendar.YEAR,2018); c.set(Calendar.DAY_OF_MONTH,20); c.set(Calendar.HOUR_OF_DAY,12); c.set(Calendar.MINUTE,10); c.set(Calendar.SECOND,2);  Intent intent = new Intent(ProfileList.this, IntentBroadcastedReceiver.class); PendingIntent pintent = PendingIntent.getService(ProfileList.this, 0, intent, 0); AlarmManager alarm = (AlarmManager)getSystemService(Context.ALARM_SERVICE); alarm.setRepeating(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), 30*1000, pintent);

In java.util.Calendar, January is defined as month 0, not month 1. Is there any specific reason to that ?  I have seen many people getting confused about that...


Prove: $$\sum_{n=1}^{\infty} \frac{1}{n^2}\cos(n x)= \frac{\pi^2}{6}-\frac{\pi x}{2}+\frac{x^2}{4}$$ for $0\le x\le 2 \pi$  I've found the result in 1.443  I.S. Gradshteyn and I.M. Ryzhik's book. But I need the proof.

Is it true that for $x\in[0,2\pi]$ we have $$\sum_{n=1}^{\infty}\frac{\cos(nx)}{n^2}=\frac{x^2}{4}-\frac{\pi x}{2}+\frac{\pi^2}{6}$$ How can I prove it? For other intervals what is the value of above series if is convergent?


I have a SQL Server instance where the service is consuming 173 GB, the max server memory is set at 60 GB. How do I determine where that memory is or if I have a memory leak?

I put SQL Server 2012 Standard on a virtual machine (VMWare) which has roughly 98GB of Memory.  Now I checked the query below how much memory is taken by SQL Server.  Microsoft SQL Server 2012 - 11.0.5058.0 (X64)    And see that he ate already 81GB of the memory and the max Memory is set to ~90GB.  Using:  select (physical_memory_in_use_kb/1024)Memory_usedby_Sqlserver_MB,       (locked_page_allocations_kb/1024 )Locked_pages_used_Sqlserver_MB,  (total_virtual_address_space_kb/1024 ) VAS from sys. dm_os_process_memory   SQL Server 2012 Standard should support only 64GB of memory.  Why does my SQL Server eat more than he can? Or is the info incorrect?  Any idea? Is that related to a virtual machine using virtual memory?   I don't know if balloon driver is activated on VM Host...  If you need any more info I will add it.


I need some help to finish this proof:  THEOREM   Let $\{a_n\}$ be such that $\lim a_n=\ell$ and set  $$\hat a_n=\frac 1 n \sum_{k=1}^na_k$$  Then $\lim\hat a_n=\ell$  PROOF  Let $\epsilon >0 $ be given. Since $\lim a_n=\ell$ , there exists an $N$ for which $$\left| {{a_n} - \ell } \right| < {\epsilon/2 }$$  whenever $n>N$. Now:  $$\begin{eqnarray*}   \left| {\frac{1}{n}\sum\limits_{k = 1}^n {{a_k}}  - \ell } \right| &=& \left| {\frac{1}{n}\sum\limits_{k = 1}^n {\left( {{a_k} - \ell } \right)} } \right| \\     &=& \left| {\frac{1}{n}\sum\limits_{k = 1}^N {\left( {{a_k} - \ell } \right)}  + \frac{1}{n}\sum\limits_{k = N + 1}^n {\left( {{a_k} - \ell } \right)} } \right|  \\     &\leqslant& \frac{1}{n}\sum\limits_{k = 1}^N {\left| {{a_k} - \ell } \right|}  + \frac{1}{n}\sum\limits_{k = N + 1}^n {\left| {{a_k} - \ell } \right|} \\   &  <& \frac{N}{n}\zeta  - \frac{{N }}{2n}\epsilon+\epsilon/2 \end{eqnarray*} $$  where $$\zeta=\mathop {\max }\limits_{1 \leqslant k \leqslant N} \left| {{a_k} - \ell } \right|$$  Now, let $n_0$ be such that if $n>n_0$,  $$\eqalign{   & \frac{{N\zeta }}{n} < {\epsilon}  \cr    & \frac{N}{n} < {1} \cr} $$ Then we get  $$\frac{N}{n}\zeta  - \frac{N}{n}\frac{\epsilon }{2} + \frac{\epsilon }{2} < \epsilon  - \frac{\epsilon }{2} + \frac{\epsilon }{2} = \epsilon $$  How far is this OK?  Do you think there is an easier way to go about proving it? I now remember that by Stolz Cesàro:  $$\mathop {\lim }\limits_{n \to \infty } \frac{1}{n}\sum\limits_{k = 1}^n {{a_k}}  = \mathop {\lim }\limits_{n \to \infty } \frac{{\sum\limits_{k = 1}^{n + 1} {{a_k}}  - \sum\limits_{k = 1}^n {{a_k}} }}{{n + 1 - n}} = \mathop {\lim }\limits_{n \to \infty } {a_{n + 1}} = \ell $$

Prove that if $\lim_{n \to \infty}z_{n}=A$ then:  $$\lim_{n \to \infty}\frac{z_{1}+z_{2}+\cdots + z_{n}}{n}=A$$ I was thinking spliting it in: $$(z_{1}+z_{2}+\cdots+z_{N-1})+(z_{N}+z_{N+1}+\cdots+z_{n})$$ where $N$ is value of $n$ for which $|A-z_{n}|<\epsilon$ then taking the limit of this sum devided by $n$ , and noting that the second sum is as close as you wish to $nA$ while the first is as close as you wish to $0$. Not sure if this helps....


I'd like to fly from Israel to Australia and to have the possibility of returning more than a year after the outgoing flight. So far the flight conditions I have checked only allow up to a year difference between the outgoing and the return flight, and even if I change the date of the return flight, I can only do this to a date which is up to a year after the outgoing flight.  Is there a way to do this without paying for two one-way flights?    The reason is that one-way flights tend to be around the same price as two-way flights and I will end up paying much more if I book two one-way flights.

Is it possible to buy an airline ticket that has me returning to my country after a year being abroad? I can't seem to book a flight that far in advance online.


This celibacy rule among the Jedi is illogical. Permitting Jedi to marry will ensure a steady supply of future Jedi which are so rare and so hard to train. Why have this rule which obviously weaken the Jedi order? Look at Anakin's offspring. Every single one of his children had Jedi powers even without much training. If Anakin had obeyed this illogical rule, the Jedi would have been weakened. Why did the Jedi have this rule and how do they ensure the Jedi do not go extinct over time as a result?

I can't seem to find a satisfactory answer to this anywhere on the web. While  poses a related question, I don't think it sufficiently answers mine...  During the opening chapters of Jedi Search, Luke addresses the new Senate on the need to find new Jedi talent, or Force sensitive individuals. During this proposal, he cites that the most fruitful leads of Jedi potential are in the descendants of Jedi Knights: as Force sensitivity is hereditary. The book even discusses the notion that Leia should be comparatively well attuned to the Force, due to her being the child of Anakin Skywalker.  I understand that the concept of the Jedi as a totally celibate and monastic order was something that was retconned into the lore after Episode II: Attack of the Clones, and that there are examples of entire nuclear Jedi families exist (such as Andur Sunrider and Plo Koon)...  But if Force-manipulative ability is passed down genetically (as a potentially mutative property of their genetic makeup), why would the Jedi order be so numerous if they practice Chastity?  Even if procreation is not expressly forbidden (as in the pre-retcon Expanded Universe): why would Jedi need special permission to produce more Jedi potential children?  How are more Jedi created, if not through procreation? Has their profusion been deliberately retarded, and if so why? is there another explanation for their (pre-empirical) plenitude?


I recently went to the Apple store with my laptop because it would only boot into safe mode and would not accept my password. While there, they said some liquid ruined something in the inside of my laptop. They said that the shift key was internally broken and will cost up to $700 to fix. Now, in order to use my laptop, I need to use an external USB keyboard.   But, whenever I turn my laptop on, it boots into Safe mode. Is there a way to disable it? I have tried holding down Esc and C and space but nothing has worked for me. Does anyone have anysuggestions?

This is an attempt to write a canonical QA for this issue, as per the Meta post:   I expect it to be periodically edited with the goal of becoming a comprehensive information resource.  I have a MacBook Pro that has a key(Shift, Return,   Command, P, etc.) that doesn’t respond when pressed or is stuck in the down position.    It's possible that my favorite beverage was spilled (or some other liquid damage).  It's also possible that I have no idea what happened.  It was working yesterday and suddenly today it's no longer working.  Is there any way to bypass or remap the key?  Can I  have the system ignore it completely?  (This question can also apply to external USB keyboards or the Bluetooth keyboards)


My computer doesn't seem to be capable of using this on a USB stick. Am I missing something here? I've followed all instructions i can find for using a USB drive but my computer will not load the .iso file at all. Am I supposed to convert it or what?

I tried to use the usb-creator.exe from Ubuntu 10.10 desktop i386 ISO image and it does create an USB stick that doesn't boot. When I try to boot from it I get:     Operating System not found.   I try to do this from Windows 7 x64. I'm not looking to create a live Ubuntu media, only an installation USB disk.  I repeated the process several times and I even tried to reformat the USB drive (FAT32), no success yet.  The USB stick is a 8GB one.


Background: CS Undergrad Applying to CS PhD Programs in the USA. I have a GPA of 8.9 ~ (after converting) 3.5? (Not too sure, I am in a Tier-II College in India). According to me, I feel a GPA of 8.9 isn't too bad, I guess I'm in the 87-93 percentile of my department. But my lowest scores are in 4 out of my 5 math papers. I only scored the best grade in my 5th semester. 2 A's, 1 B, 1 A, 1 O (Hierarchy of Grades: O A+ A B B+ C .. F) I know CS PhD admit panels require mathematically sound students and I actually am quite good at math. The few preprints and publications I have are all in mathematically involved topics. They are primarily machine learning but quite a bit of math is involved. It is pure coincidence that I actually somehow managed to perform bad specifically in the math papers. I have good grades in my computer science subjects, good SOPs and LORs (at least I think I do, they will be research dense), internships. Question:  Does this really affect my chances of getting into a good program? Is there any way I can offset this? Does a good GRE Quant score help in this? (Don't mind my asking)  Extra Question: Should I opt for a master's, get good grades in the math subjects there and better my transcripts? (I really want to start a PhD and skip my masters. I enjoy research a lot). Sorry for so many questions, I really need some clarity. I am also aware Machine learning is mostly math, what I meant to say was that the papers are not only code heavy but also contain good theory.

When applying to a PhD program in the US, how does the admissions process work? If an applicant is weak in a particular area, is it possible to offset that by being strong in a different area?  Note that this question originated from this . Please feel free to edit the question to improve it.


I have a school project about cryptography. The question is the following (will only give a short phrase as example, just want to know the method). A text has been encoded with Vigenere 2 times. The ciphertext is FXFCKDKFCLMHOSPERVBOPDJ (it's Dutch btw, you won't really get plausible words because I cut it off). It has first been encoded with a cipher of 3 letters, and then with a cipher of 2 letters. The first letter of the 2nd cipher is an O.

I have been learning about Vigenere ciphers and then thought of this scenario: if a cryptographer encrypts a plaintext English message with a Vigenere cipher and then another cryptographer, who wants to ensure that the message is very secure, encrypts the ciphertext with another Vigenere cipher (with a different key length). Given only the ciphertext, how can you decrypt the message? A step by step explanation would be greatly appreciated.


I've read an article saying that when using planned contrasts to find means that are different in an one way ANOVA, constrasts should be orthogonal so that they are uncorrelated and prevent the type I error from being inflated.  I don't understand why orthogonal would mean uncorrelated under any circumstances. I can't find a visual/intuitive explanation of that, so I tried to understand these articles/answers        but to me, they contradict each other. The first says that if two variables are uncorrelated and/or orthogonal then they are linearly independent, but that the fact that they are linearly independant does not imply that they are uncorrelated and/or orthogonal.  Now on the second link there are answers that state things like "orthogonal means uncorrelated" and "If X and Y are independent then they are Orthogonal. But the converse is not true".  Another interesting comment in the second link state that the correlation coefficient between two variables is equal to the cosine of the angle between the two vectors corresponding to these variables, which implies that two orthogonal vectors are completely uncorrelated (which isn't what the first article claims).  So what's the true relationship between independence, orthogonal and correlation ? Maybe I missed something but I can't find out what it is.

I know what it means to say two variables are independent, but can't understand what does it mean to say two variables are orthogonal.Can anyone help me?


I have given someone my bank account details including my home address and phone number by email, supposedly so that money can be transferred into my account.  I am now quite sure this is a scam.  What do I do next, i.e. how do I protect myself from this scammer?

Updated question because old one was embarassing: I saw a spam email from "PayPal" and I didn't realize that it was a phishing attempt. I gave the phishing site my name, telephone number, and email. What could he do with them?  Old question: Well, I saw a spam email, but I didn't realize that it's really a scam at first. I gave him my telephone number, address, and name. What would he do with them? Could he ruin ALL of my reputation with it?


I have some function to execute which might take longer time.  What i want to do is if the given function is taking more than 5 second then terminate this task and execute some another function.  if (function(a) > 5 seconds)     function(b) else     function(c)

I'm calling a function in Python which I know may stall and force me to restart the script.   How do I call the function or what do I wrap it in so that if it takes longer than 5 seconds the script cancels it and does something else?


I use acronym package in my Latex file. Strangely, some of its commands, like \Ac are not defined when I compile my file. The \ac command works fine though.  \documentclass[12pt]{extarticle} \usepackage[printonlyused]{acronym} \usepackage{multicol}  \title{Physical Layer Security}  \begin{document} \maketitle \Ac{BER} is a metric.   \section{Acronyms} \begin{multicols}{2}     \begin{acronym}              \acro{BER}{bit-error rate}     \end{acronym} \end{multicols}  \end{document}   And here is the error I see:  ! Undefined control sequence. \Ac

I'm using the acronym package in my document and in several instances I want to start a sentence with the expanded acronym. Is there any way of telling the package to capitalise the first letter?  For example:  \acrodef{TLA}{three-letter acronym} \acrodefplural{TLA}{three-letter acronyms} ...end of one sentence. \aclp{TLA} are acronyms with three letters...   This will yield:     ...end of one sentence. three-letter acronyms are acronyms with three letters...


I could not find a way to stepwise regression in scikit learn. I have checked all other posts on Stack Exchange on this topic. Answers to all of them suggests using f_regression.  But f_regression does not do stepwise regression but only give F-score and pvalues corresponding to each of the regressors, which is only the first step in stepwise regression.  What to do after 1st regressors with the best f-score is chosen?

I'm working on the problem with too many features and training my models takes way too long. I implemented forward selection algorithm to choose features.  However, I was wondering does scikit-learn have forward selection/stepwise regression algorithm?


<script type="text/javascript">  var a = new Array( "Jane", "Tom,",  "Alan,", "Mary"); </script> <script type="text/javascript"> document.write(a[Math.floor(Math.random()*a.length)]); </script>  ate an apple     Is there away of reusing the answer to (a[Math.floor(Math.random()*a.length)]) later on in a script?     So for example I could later use text along the lines of Harry asked "answer" if they had enjoyed the apple

How do I generate a random int value in a specific range? I have tried the following, but those do not work: Attempt 1: randomNum = minimum + (int)(Math.random() * maximum);  Bug: randomNum can be bigger than maximum. Attempt 2: Random rn = new Random(); int n = maximum - minimum + 1; int i = rn.nextInt() % n; randomNum =  minimum + i;  Bug: randomNum can be smaller than minimum.


Just... take a look at this, please:        , see sidebar. (It's much worse there, my screen recording frame rate isn't great.)  I think it's needless to say... but: it's irritating, and I don't want to see animations there.

It has been discussed previously that animated avatars are disliked because they cause a distraction from the content. However, currently animated avatars are not treated consistently.   On desktop, animated avatars are displayed as a still image, both in posts and on the profile page. On mobile, animated avatars are displayed as a still image in posts, but animated on the profile page.   I'm tagging this  because I'm guessing one of these two is unintended. Either avatars should animate on the profile page on both desktop and mobile, or on neither. (I sincerely hope that we are all agreed there should be no animation of avatars in posts.)  Example animated profile    This appears to animate on mobile, and show a still image on desktop (for myself and for other users who have tried).    I'd also like to hear arguments for and against animating only on the profile page, but the main purpose of this post is to clear up the inconsistency.


I have just recently installed Light Table downloading it from the git repository, and followed the instructions on  to create a desktop launcher.   Now I want to run the program by directly typing in the terminal  LightTable   and not  ./opt/LightTable/deploy/LightTable

How do I add a directory to the $PATH in Ubuntu and make the changes permanent?


e (Euler's number) is defined commonly in calculus and in continuous interest as:  $\lim_{n\to∞} \left(1+\frac{1}{n}\right)^n$  Why does this limit not approach 1? Since as n approaches infinity, $\frac{1}{n}$ approaches zero, hence $\left(1+\frac{1}{n}\right)$ approaches 1, and since $1^n=1$ for all cases of n, wouldn't the limit therefore be 1?

I am trying to identify what the flaw is exactly when reasoning about a limit such as the definition of $\mathbf e$:  $$ \lim_{n\rightarrow \infty}\left(1+\frac{1}{n}\right)^n={e} $$  Now, I know there are ways of proving this limit, such as by considering the binomial expansion of $(1+\frac{1}{n})^n$ and comparing that to the Maclaurin series of $e$. So to make this clear, I am not looking for a proof of the limit definition of $e$.  I tried searching for "limit laws/rules" but none of the rules I found described the above case. Hence, I am looking for a specific rule (or perhaps a certain perspective) that will help me realize why the above does not in fact evaluate to 1.  My train of thought is as follows: at a first glance, if I wasn't already familiar with what the limit evaluates to, I probably would evaluate the expression inside the brackets first, and then apply the limit to the power. So, $$\displaystyle\lim_{n\to\infty}\frac{1}{n}=0\quad\text{and then}$$  $$\displaystyle\lim_{n\rightarrow \infty}\left(1+0\right)^n=\lim_{n\to\infty}1^n=1$$  Why is my reasoning flawed?


I wondered if the centroid of an area could be derived as a limit from the centroid of the solid of revolution built by the same area revolving around an axis of revolution.  e.g.: the volume centroid of a spherical wedge is $C_{V} = \frac{3\pi}{16}r\frac{\sin[\theta]}{\theta}$, where $r$ is the radius of the sphere and $\theta$ is the dihedral angle. The centroid of a semicircular lamina is $C_{A} = \frac{4r}{3\pi}$  Now I tought it was possible a limit procedure like $\lim\limits_{\theta\to 0} C_{V}$=$C_{A}$, but that's false and I would like to know why (I guess that has something to do with the passage from three-dimension to two-dimension)  Thanks

I wondered if the centroid of an area could be derived as a limit from the centroid of the solid of revolution built by the same area revolving around an axis of revolution.   e.g.: the  is $C_{V} = \frac{3\pi}{16}r\frac{\sin[\theta]}{\theta}$, where $r$ is the radius of the sphere and $\theta$ is the dihedral angle. The  is $C_{A} = \frac{4r}{3\pi}$  Now I tought it was possible a limit procedure like $\lim\limits_{\theta\to 0} C_{V}$=$C_{A}$, but that's false and I would like to know why (I guess that has something to do with the passage from three-dimension to two-dimension)  Thanks


Is there a word for a term employed to play for time and allow the speaker a little longer to work out what he/she wants to say next?  Words like um and er fall into this category, of course, but so (sometimes) do terms like actually, obviously, you know, like...  I wondered about filler word, but that would cover other reasons for using such a term. It's more about the grammatical relation to the rest of the sentence (none at all) rather than the purpose for which the speaker is using it.

Examples:  Anyway, after that I went home and went to sleep. Anyhow, do you want to go for a drink? So then, I was chatting to this girl and... Now, Bob was a nice guy, but socially inept. Her cooking was, well, terrible.  These words are distinct from fillers like 'umm' and 'err' because they are often used intentionally in written, usually informal, English, such as writing expressing a conversational tone.


Inspired by  and my answer.  The standard formula for binomial coefficients is well-known: $$\binom{n}{r} = \frac{n!}{r!\cdot (n-r)!}.$$ And the binomial theorem is one of the more prominent uses of binomial coefficients: $$(x + y)^n = \sum_{r = 0}^n\binom nr x^{n-r}y^{r}.$$ However, when using the binomial theorem modulo some integer $k$ (i.e. when working with polynomials over $\Bbb Z_k$ rather than $\Bbb Z$), one encounters a problem putting these two things together. Specifically, if $n$ is large enough, the fraction in the formula for binomial coefficients is invalid, as the denominator will not be invertible modulo $k$.  Now, one could argue something along the following lines: $\binom nr$ as given in the formula represents an integer. One uses the formula over the integers to find the integer value of the binomial coefficient, and then reduce it modulo $k$. This approach will give the correct answer.  However, this doesn't sit entirely well with me. When expanding $(x + y)^n$ in $\Bbb Z_k[x, y]$, in any intermediate step as well as in the final answer, all coefficients are in $\Bbb Z_k$. The integers never really enter into this1.  So my question is this: Is there a (relatively) compact formula2 for $\binom nr$ modulo $k$? Every arithmetic operation the formula describes ought to be valid modulo $k$, so most importantly there should be no factors of $k$ in any denominators.  A first attempt might be to clear away factors from the original formula. This way we get then: $$ \binom nr = \frac{n(n-1)(n-2)\cdots(n-r+1)}{r!} $$ Once we get to this point, though, any more simplification of factors seems to be very difficult. And while this formula is a bit more robust (its validity is independent of the size of $n$, for one thing), it still won't work for large enough $r$.    1 Many (most?) people, on some level, actually do the modular addition and multiplication required for this expansion the way described above: think integers first, then reduce modulo $k$ afterwards. But my point is that one does not have to do it that way.  2 Say it should be simple enough that using it to calculate binomial coefficients up to around $n = 10$, or with $r$ close to $0$ or to $n$, with pen and paper should not be tedious, whatever that means. And while I don't expect there to be something as short as $\frac{n!}{r!(n-r)!}$, I don't want there to be any problems fitting it in a single line.    Edit: I was made aware of  in the comments. This neatly solves the problem for prime $k$ (and by the Chinese remainder theorem for square-free $k$). I guess my remaining question is this: Can something be done for $k$ being the power of a prime? And if I'm being greedy, I personally think using the Chinese remainder theorem for calculations is a bit tedious at times. Can one make do without it? (This is in no way a requirement; a full solution using the CRT is completely fine. It might also be just me not having found an algorithm I'm comfortable with, which is another issue enteirely.)

I don't really see too many sites explaining how this is done. Does anyone know how this works? I'm trying to find $\binom{n}{k}\bmod m$, where $n$ and $k$ are large and $m$ is not prime. I think it can be done with the Chinese remainder theorem, but I don't understand how it is all put together.


=QUERY('F/O OFF'!1:1000, "select H, J where B='CIN'label H'', J''")   Right now this formula works fine,  but i have to change the "where B=" for each row in the sheet.   I want to get it so where B= (The value in colA of the row the query is being inputted in)

I'm having trouble figuring out a fairly simple QUERY statement in Google Spreadsheets. I'm trying to use a cell reference instead of static values and I'm running into trouble. I keep getting Error: Formula parse error. with:    =QUERY(Responses!B1:I, "Select B where G contains"& $B1 &)   I'm sure it is a simple error, but can someone please show me how to write the above so the QUERY is pulling data from B where G contains the value in cell B1 (cell reference)?


There is a way in order to reproduce this graphic in with tikzpicture? Which is the best way?

What packages do you use and recommend for creating graphics in your LaTeX documents?     As this is a community wiki post, please add your package to the accepted answer (or add a comment, and someone with >100 rep will add it to the CW answer), and include a brief description of what differentiates it from others and how it can be used (GUI drawing tool which generates code, type in raw text, or generates image for inclusion in document).   We'll eventually sort these answers under headings.


I'm trying to make an app for my project on android studio, but when I'm trying to run this java file, this file is crashing and app stopped working on my emulator.Im simply trying to import images from my default gallery to my app.  import ....   public class tenant_profile extends Fragment {  private final int SELECT_PHOTO = 1; private ImageView imageView; public tenant_profile() {     // Required empty public constructor }   @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,                          Bundle savedInstanceState) {      // Inflate the layout for this fragment      super.onCreateView(inflater, container, savedInstanceState);      return inflater.inflate(R.layout.fragment_tenant_profile, container, false); }   @Override public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);        Button pickImage = (Button) getView().findViewById(R.id.btn_pick);     pickImage.setOnClickListener(new OnClickListener() {     //enter code here         @Override         public void onClick(View view) {             Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);             photoPickerIntent.setType("image/*");             startActivityForResult(photoPickerIntent, SELECT_PHOTO);         }     }); }      @Override     public void onActivityResult ( int requestCode, int resultCode, Intent imageReturnedIntent){         super.onActivityResult(requestCode, resultCode, imageReturnedIntent);          switch (requestCode) {             case SELECT_PHOTO:                 if (resultCode == Activity.RESULT_OK) {                     try {                         final Uri imageUri = imageReturnedIntent.getData();                         final InputStream imageStream = getContext().getContentResolver().openInputStream(imageUri);                         final Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);                         imageView.setImageBitmap(selectedImage);                     } catch (FileNotFoundException e) {                         e.printStackTrace();                     }                   }         }     }    }   My exception is following:  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime: FATAL EXCEPTION: main  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime: java.lang.NullPointerException  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at com.example.sanchit.helloworld.tenant_profile.onCreate(tenant_profile.java:55)  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.Fragment.performCreate(Fragment.java:1939)  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:988)  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1207)  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1572)  01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:493)   please help

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


This is a simple password app, and it's not really working, i'm not sure what most of this sentences mean. I have some knowledge in c++ but this is new to me. Can somebody correct me? I can't find a site that explains this well.          public void addListenerOnButton(){      geslo = (EditText) findViewById(R.id.password);     Gumb  = (Button) findViewById(R.id.Gump);      Gumb.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View view) {         String text="banana";         if(geslo.toString()==text){             Intent newactivity= new Intent(MyActivity.this,MainDatoteka.class);             startActivity(newactivity);         }         }     }); }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I’m using Ubuntu 14.04.  I have this in my /etc/sudoers file  Defaults        env_reset Defaults        mail_badpass Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL %deployers ALL=(ALL) ALL  rails ALL = NOPASSWD: /usr/local/rvm/gems/ruby-2.3.0/bin/bundle, /usr/local/rvm/rubies/ruby-2.3.0/bin/ruby, /usr/local/rvm/gems/ruby-2.3.0/bin/rake, /usr/bin/service, /sbin/   restart  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL   I thought including the above command (the one with “NOPASSWD”) would prevent getting prompted for a password, but after I reboot my system and login as my “rails” user, note I’m still getting asked for a password when running sudo …  rails@mymachine:~$ sudo rake db:migrate [sudo] password for rails:  rails@mymachine:~$ which rake /usr/local/rvm/gems/ruby-2.3.0/bin/rake   What do I need to do so I’m not prompted for a password when running the “rake” command (and other commands I listed)?

I need to run something as sudo without a password, so I used visudo and added this to my sudoers file:  MYUSERNAME ALL = NOPASSWD: /path/to/my/program   Then I tried it out:  $ sudo /path/to/my/program [sudo] password for MYUSERNAME:    Why does it ask for a password? How can I run/use commands as root with a non-root user, without asking for a password?


I am new in Javascript and I don't know much about the js programming. I am thinking of separate 12.13 into two-part 12 and 13 from the dot in javascript.   I found on the website separate string into two-part but I don't know how to do with the integer.     For example,  var i = "12.13" var t = i.split("");

I have this string  'john smith~123 Street~Apt 4~New York~NY~12345'   Using JavaScript, what is the fastest way to parse this into  var name = "john smith"; var street= "123 Street"; //etc...


I have a simple templated class with private generic vector and I wanted to expose begin and end iterators (in order to consume these outside that class in std:accumulate).  I am trying to achieve it like so:  #include <vector>  template <typename T> class MyClass  { public:     std::vector<T, std::allocator<T>>::iterator begin() { return m_data.begin(); }     std::vector<T, std::allocator<T>>::iterator end() { return m_data.end(); }     //...  private:     std::vector<T> m_data;     //... };   But it seems that I am doing something wrong as it doesn't compiles and reports following:  C2146: syntax error : missing ';' before identifier 'begin'  C4430: missing type specifier - int assumed. Note: C++ does not support default-int C2146: syntax error : missing ';' before identifier 'begin'  C4430: missing type specifier - int assumed. Note: C++ does not support default-int   That makes absolutely no sense for me, can you point me to how begin can be exposed?

In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template <typename T, typename Tail> // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template<typename U> struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion<U> dummy;      };     template< > struct inUnion<T> {     }; }; template <typename T> // For the last node Tn. struct UnionNode<T, void> {     // ...     template<typename U> struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template< > struct inUnion<T> {     }; };   The problem I have is in the typedef Tail::inUnion<U> dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion<U> names a type and not a function?


$\sqrt{a_1}, \sqrt{a_2} ,\cdots, \sqrt{a_n}$ are irrationals and $a_1,a_2,\cdots,a_n$ are integers $>1$. I didn't find any proof for this exercise. Please help!!

Assume that $a，b，c, \sqrt{a}+ \sqrt{b}+\sqrt{c} \in\mathbb Q$ are rational，prove $\sqrt{a},\sqrt{b},\sqrt{c}  \in\mathbb Q$,are rational.  I know that can be proved, would like to know that there is no easier way    $\sqrt a + \sqrt b + \sqrt c = p \in \mathbb Q$, $\sqrt a + \sqrt b  = p- \sqrt c$, $a+b+2\sqrt a \sqrt b = p^2+c-2p\sqrt c$, $2\sqrt a\sqrt b=p^2+c-a-b-2p\sqrt c$, $4ab=(p^2+c-a-b)+4p^2c-4p(p^2+c-a-b)\sqrt c$, $\sqrt c=\frac{(p^2+c-a-b)+4p^c-4ab}{4p(p^2+c-a-b)}\in\mathbb Q$.


hi i am unable to get complete url using Query Sting in asp.net C#. This is due to '#'.  My url look like ID=OOP-Concepts-in-C#:-Code-Examples-and-How-to-Create-a-6  Code :string Qstring=Request.QueryString["ID"].ToString();  from this i am getting only "OOP-Concepts-in-C". After '#'(include # too), unable to get the string. Please help

I know on client side (javascript) you can use windows.location.hash but could not find anyway to access from the server side. I'm using asp.net.


I'd like to write better bug reports - what are some things I should keep in mind when reporting bugs to developers of software I use?

I want to write (or find) a guide to effective bug reporting in a style similar to ESR's   What are your top tips for effective bug reports?


Coming at BLDC motors from the theory side, my understanding has always been that they have a linear curve based on Kv, no-load current, and resistance, for a given applied voltage. Now the thing is, say they have a given "system load", like a propeller, that varies during the operation. So the load demands a certain RPM/torque combination at time A, and then a different one at time B. My understanding was that in order to achieve both combination A and B, it has to vary the supply voltage so that it's linear torque-speed curve intersects this operating point (provided this point lies below it's highest torque-speed curve). What I can't seem to find is how this works without changing the supply voltage? If I use a PWM controller at 50% (but the supply voltage is the same), is the torque-speed curve really going to have a characteristic curve that responds as if the supply voltage was half? If not, how are these BLDC motors controller for dynamic applications where a specific torque and speed are needed at different times?

1.) I have a brushless motor with testing data at 12V. I want to know if I increase the voltage supply, will this increase the torque?   In my research I keep seeing "current controls torque, and voltage controls speed." But that doesn't seem quite right. Let's say I have a theoretical electrically powered unicycle that is weighted. With a 5V source and 2A, the motor can't move the unicycle. But now I increase the voltage to 10V, and I believe current will also increase by x2 if resistance is constant (V = IR). So now the torque increases and the unicycle can move itself. It that a reasonable sequence of events? Can I say that increasing voltage increases torque?   2.) A similar question: if P = VI = tau*omega, then P/omega = tau, so:  2*(P/omega) = 2*tau, which means increasing power will increase torque, correct? And since P = VI, increasing V will increase P, which will in turn increase torque. Is this accurate at all?


Pls, let me know if is possible to create this kind of query. I never saw something like that  Pls, check below the image. It´s exactly what I need to do!

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


So I seem to be struggling a little bit with static in general. What exactly does static do in Java and how do you fix it? For example, here is a bit of code  public class StaticProblem {     static int number;     static int valOne, valTwo, valThree;      public static void main(String args)     {         // stuff          valOne = method1(number);         valThree = method2(val1, val2);     }      public static int method1(int parameter)     {         int var;         // stuff         return parameter + var;     }      public static int method2(int parm1, int parm2)      {         int othervar;         // more stuff          return parm1 + parm2 + othervar;     }      : }   How exactly would one go about fixing the "static" problem so that static is no longer used. I sort of understand that static in Java allows the value of one object to be shared with new objects that are created (for example, 15 cards all share the same gas left in the tank - if one car goes empty, then the rest go empty as well). I thought I knew how to fix this code and I assumed it involved making a new StaticProblem object in the main method. However, I am a bit lost.

To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?


I would like to access a remote host using a short name. On a system where I have admin rights, I would achieve this by adding an entry in /etc/hosts file, something like this  121.121.122.1  shortname  Is it possible to achieve this using some other method which does not require modifying /etc/hosts or other admin level or system wide changes?

Is it possible to add a list of hosts that are only specific to a certain user? Perhaps a user-specific hosts file?  This mechanism should also complement the entries in the /etc/hosts file.


how to get blender cars,furnitures,trees etc free ? if you know any sites or links , then please answer me , am already try blender market , but i think thats must need money then am post this question

Is there any place where I can download surroundings of a game as a 3d model or maybe there re some inspired artists where they put them for download. I'm trying to find rooms from Wall-e. Some rooms, or outside surroundings or some interior surroundings. Where can I find things like that?


I have a problem I've been searching SO for answers to, but nothing seem to do it for me. I've referenced a question that mimics my problem but the solution still don't solve my problem.    My problem is as I've mentioned similar. I can't access a method inside a script file from another script file. These are my codes:  page.js  $(document).ready(function () {     $.getScript('script.js').done(function () {         $('#build').append(literals.test()); // $('#build') is a span tag in the HTML-file.     }).fail(function () {         console.warn('Unable to load script file.');     }); });   script.js  (function ($) {     var literals = {             test: function () {                 return 'Hello world!';             }         }; })(jQuery);   This still returns the following error even though I've built it almost exactly the same way as in the answer of the referenced question.  Uncaught ReferenceError: literals is not defined at Object.<anonymous>   What am I doing wrong here?

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I'm aware that this question has been answered here    But I want to prove this result a different way.   Suppose that $\mathcal{B}$ is separable and define $i : \mathcal{B} \to L^{\infty}(\mathbb{N})$ in the following way: For a dense subset of the unit ball in $\mathcal{B}$, denoted by $\{ f_n \}$, define $x_n = (\cdot, f_n)$ and thus define $i(y) = ((y,f_n))_{n=1}^{\infty}$. It is clear that this map is linear, injective and that $\| i(y) \|_{L^{\infty}(\mathbb{N})} = \| y \|_{\mathcal{B}}$. It remains to show that $i$ is bounded. This is where I'm stuck.

The problem is:  Let $X$ be a separable Banach space then there is an isometric embedding from $X$ to $\ell^{\infty}$.  My efforts:  I showed that there is an isometry from $X^*$ (topological dual) to $\ell^\infty$ in the following way:  Let $(e_{i})_{i=1}^{\infty}$ be a dense sequence in $B_{X}$ then define $\Phi:X^*\rightarrow\ell^\infty$ by $\Phi(f)=(f(e_{i}))_{i=1}^\infty$.   It is clear that $\Phi$ is an isometry.  An initial idea and a secondary question  Is there any canonical isometry from $X$ to $X^*$ since $X$ is separable (or not)?


I have read through questions concerning installing driver for this wireless adapter, and found that the driver is closely dependent on the details of each adapter, thus I post my adapter here and ask for specific instructions. If further information is needed, please let me know, thanks!  I just followed the answer provided by Ben Lee in  to try installing the driver. Every step is successfully done except for the last step, where I enhanced it with sudo modprobe 8192du. I then restarted the computer, but it seems it does not work. Even the light on the Belkin adapter is not turned on (in Windows, the light labelled with ((|)) will be on to show that it is at least working). Thanks for further help!  lsusb gives the following information,  $ lsusb Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 002: ID 3938:1031   Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 003: ID 050d:615a Belkin Components F7D4101 / F9L1101 802.11abgn Wireless Adapter [Broadcom BCM4323] Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

I have an old Compaq desktop that my children use to access the internet. The kids have repeatedly managed to severely infect the computer with viruses, and this latest round has been a doozy. A friend recently sold me on Ubuntu as a great windows replacement since it is not prone to viruses, so I decided to to give it a go.  I completely overwrote windows with Ubuntu 12.04 to get rid of the viruses, but I can not figure out how to make the wireless network dongle work. I have Googled the topic and tried to go through some of the solutions, but I don't know what I'm doing and I think I may be making things worse. Can someone help me with this? I know NOTHING about Linux and most of the instructions aren't written for someone like me.  Thanks,  lsusb gives the following:  Bus 001 Device 004: ID 050d:615a Belkin Components F7D4101 / F9L1101 802.11abgn Wireless Adapter [Broadcom BCM4323] Bus 005 Device 002: ID 045e:0040 Microsoft Corp. Wheel Mouse Optical Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub   Thanks for helping me with this chili!


Fellow geometry enthusiasts:  I am studying a particular geometry and I would like to change from one set of coordinates to a new set that makes the metric unimodular (i.e. it's determinant is one). The components of the metric are rather complicated functions of the coordinates, so I don't know how to solve the system of linear first order PDEs that I get from the Jacobian. Is anyone aware of any software that can give me the new coordinates in terms of the old ones given the Jacobian of the transformation? I have Maple 18, but I have not been able to find this capability in Maple.

What is some good free software for doing physics calculations?  I'm mainly interested in symbolic computation (something like Mathematica, but free).


This is a part of my code:  $content = ' '; $content .= '<meta http-equiv="content-type" content="text/html;charset=UTF-8"/></meta>         <link rel="stylesheet" href="" type="text/css" media="screen" /> <div class="all_block">';   Don't work UTF-8 but it is set I don't understand where is my problem This is an example of text: 'ja?i ku?ol har? lerp�' Help me please!

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I want to force my cellular modem to transmit at maximum power so that I can see if that is the cause of microSD card crashes that I have been experiencing in an embedded application.  My modem is a ublox U-260, and the AT command manual for it is .  I know that the modem "throttles" its transmission power based on the intensity of the received signal (from the cell tower) so you can force the modem to transmit at maximum intensity by putting it somewhere with poor cell reception.  I have been unable to get my cell reception to be bad, however, as there are a number of cell phone towers nearby.  So, seems to me there are two options:   Physical solution: Attenuate cellular signals arriving from cell tower to modem via some type of physical solution Software solution: Force the modem to transmit at maximum power levels regardless of strength of received signal by configuring it to do so via AT command (software solution)   So, anyone out there know how to implement one of these solutions?  I have tried building a faraday cage around the modem by lining the enclosure that it's in with aluminum foil and attaching an alligator clip to mains ground.

I'm currently developing an internet of things device that utilizes a uBlox SARA-U260 gsm/3G modem.  In field testing, we have had significant software/firmware issues due to poor cell phone reception in our deployments in sub-saharan Africa.  I'm having a hard time duplicating the problems in the lab because the cell reception here is too good.  Even if there is no antenna plugged into the modem, it is still able to connect to the cell network internet!  So, I'm looking for the best way to thwart my modem into thinking it has bad reception.  One thought I had was to cut the coax cable of the antenna and solder a resistor between the gnd shroud and the center conductor.  Would this work?  What size resistor would make sense? Probably a fairly low-value resistor (say 50 ohm?)  I'm confused about why the modem can still connect even without an antenna.  I thought that during normal operation the modem must short the ground and center conductor when it is transmitting (hence the high current associated with a transmission burst).   Under normal circumstances, is the short locate inside the antenna?  If so, wouldn't the center conductor of the coax always be at ground potential (i.e. during reception)?  EDIT:  Thanks for the replies.  I have a big metal box sitting on my desk ready to mount the DUT (thanks for that acronym @Ali Chen ) tomorrow!


guys! I have a little question here. I'm currently running Ubuntu 17.10 (no LTS).  I'm curious since Ubuntu 16, is it possible to add Application or Shortcut or anything beside folders on the desktop?  Really appreciate for any answers you all guys! Thanks for reading.

In older versions it was easy to create a launcher on my desktop. All I had to do is right click on my desktop and select the "create launcher" option.  How can I create such launchers now?


when I cd to / and enter the command:  ls -ls   For some files/folders it gives output like  0 lrwxrwxrwx.   1 root   root         7 Jan 30  2018 bin -> usr/bin   So what actually is this lrwxrwxrwx?

I want to know how to see the permissions a particular file has. Which command should I type in the terminal? However, I don't want to change it.


$$\lim_{n\rightarrow\infty}\sum_{k=1}^{n}\frac{1}{k+n}$$  Could you please give me a hint how to find this limit?

What is the sum of the 'second half' of the harmonic series?  $$\lim_{k\to\infty}\sum\limits_{n=k+1}^{2k}{\frac{1}{n}} =~ ?$$  More precisely, what is the limit of the above sequence of partial sums?


You can define some discontinuities and then eliminate the global max, but there is some function that have a unique critical point, this critical point is a local max (or minimum), and this function don't have a global maximum or minimum? Can you give some examples or maybe a reason because is not possible?

I was wondering if this is true.     Let $f:(a,b) \rightarrow \mathbb{R}$ be a continuous real function and suppose $c \in (a,b)$ is the unique local maximum of $f$ and that $f$ has no other local extremum. Then $c$ is also an absolute maximum of $f$. The statement is analogous for minimums.    I have no idea how to prove this, nor have I thought of any counterexamples, though I am certain that the assumption of continuity is essential; otherwise consider something like $f:(0,\frac 32) \rightarrow \mathbb{R}$ given by  $$f(x) = \begin{cases} 1 - \frac x2 &  x≤1 \\ \sqrt{\frac{1}{16} - (x-\frac 54)^2} &  x>1 \end{cases}$$  which admits a unique local maximum at $x=\frac 54$, no local minimum, but no absolute maximum.  Note that a similar question was asked  but the answers were not satisfactory and OP did not specify whether the interval was open or closed.


I'm trying hard to write a regex that should catch any http address. (background: I'd like to use it in a tkinter window, a simple editor, to transform an http address into a clickable link) Due to how complicated they can be, which is the better regex?  alessandro

How can I check if a given string is a valid URL address?  My knowledge of regular expressions is basic and doesn't allow me to choose from the hundreds of regular expressions I've already seen on the web.


Is there an uncountable collection of compact disjoint subsets of the real line such that each element of the collection is uncountable?  Thanks.

Does there exists an uncountable family $\mathcal{A}$ consisting of uncountable compact subsets of $\mathbb{R}$ and pairwise disjoint?


I am trying to write a function to print std::vectors as  template <class T> void PrintVector(const std::vector<T> vec) {      for(unsigned int j=0;j<vec.size();j++){ std::cout << vec[j] << "\t"; }      std::cout << "\n"; }   This works if I put in the main file of the project. However when I put it in an external file (e.g. functions.cpp and functions.hpp) as  File functions.hpp:  #ifndef functions_hpp #define functions_hpp  #include <iostream> #include <vector>  template <class T>  void PrintVector(const std::vector<T> vec);  #endif    File functions.cpp:  #include "functions.hpp"  template <class T> void PrintVector(const std::vector<T> vec) {      for(unsigned int j=0;j<vec.size();j++){ std::cout << vec[j] << "\t"; }      std::cout << "\n"; }   I receive the following compile error:  Undefined symbols for architecture x86_64: "void PrintVector<int>(std::__1::vector<int, std::__1::allocator<int>   >)", referenced from:   _main in main.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see     invocation)   All the other functions defined in functions.cpp work. How to solve this issue?

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I'm not sure if there is already an answer to this particular question, but here it goes,  (Definition of convexity that is used here:  Let $D \subset \mathbb{R}$ be an (infinite or finite) interval. A function $f:D\longrightarrow \mathbb{R}$ is called convex if for any $x_1,x_2 \in D$ and any $\lambda$ with $0<\lambda<1$,  $$f(\lambda x_1+(1-\lambda)x_2)\leq \lambda f(x_1) + (1-\lambda) f(x_2)$$ is valid )   The following was already proven:   In an interval $I \subset S $ continuous function $f:I \longrightarrow \mathbb{R}$  is then convex if and only if   $(1)$ $$f\bigg(\frac{x+y}{2}\bigg)\leq\frac{f(x)+f(y)}{2} $$ for any $x,y \in I$.  In the proof, the ( -> ) part is almost direct by setting $\lambda=\frac{1}{2}$ into the definition of convexity. But as for ( <- ) I had to use the continuous property of the function, but I wonder if the property $(1)$ stated above actually implies continuity so that the theorem above doesn't need to state the continuity property, as of:   In an interval $I \subset S $ function $f:I \longrightarrow \mathbb{R}$  is then convex if and only if   $(1)$ $$f\bigg(\frac{x+y}{2}\bigg)\leq\frac{f(x)+f(y)}{2} $$ for any $x,y \in I$.  I tried also to find counterexamples but to no avail, as it is for me rather intuitive that the property $(1)$ should imply continuity but I'm not sure, maybe the proof can be similar to the proof of "convexity implies continuity". I would love to see some counterexamples (assuming they exist) or perhaps the proof. Thank you very much in advance!

Rudin's Real and Complex Analysis Chapter 3 Exercise 4 is:  Assume that $\varphi$ is a continuous real function on $(a,b)$ s.t. $$\varphi\left(\frac{x+y}{2}\right)\leq \frac{\varphi(x)+\varphi(y)}{2}$$ for all $x,y\in(a,b)$. Prove that $\varphi$ is convex.   The conclusion does not follow if continuity is omitted from the hypotheses.  My question is, is there some way to explicitly construct a counterexample such that  $\varphi\left(\frac{x+y}{2}\right)\leq \frac{\varphi(x)+\varphi(y)}{2}$ for all $x,y\in(a,b)$, but $\varphi$ is not convex?


Can someone explain why the below loop in main() does not terminate  #include <iostream>  enum day { Sunday,     // 0 Monday,     // 1 Tuesday,    // 2 Wednesday,  // 3 Thursday,   // 4 Friday,     // 5 Saturday,   // 6 not_a_day   // 7 };  day operator++(day d) {     d = (day)(d + 1);     return d; }  int main() {     day d;     d = Sunday;     while (d <= Saturday) {         ++d;     }     std::cout << d << std::endl;     return 0; }   When I change the overloaded operator to use references, it works as expected, returning 7.  day &operator++(day &d) {     d = (day)(d + 1);     return d; }   Example taken from .  I also do not understand why the compiler is able to cast day to an int with the + operator, but is not able to do so for ++?

What is the difference between    a parameter passed by reference a parameter passed by value?   Could you give me some examples, please?


As an iOS developer I have many (>150) apps installed on my iPhone. Sometimes I cannot figure out on which home screen an app is located.  I know how to start the app by using the search. And if the app uses a lot of storage I can go to "Settings -> General -> iPhone Storage" and delete it.  But is there any way to find the installed app in the spring board without looking at every home page and in every folder?

In older versions of iOS, if I searched for an app with Spotlight, it would tell me which folder the app was in. (E.g., this feature still works on my iPad, which is running iOS 9, but not on my iPod Touch, which is running iOS 11.)  This feature seems to have been removed at some point. When I search for an app under iOS 11 using Spotlight, it will find the app and let me run it, but it doesn't tell me which folder it is in.  How can I find out which folder an app is in now?


Is SE Q&A format relevant for "identification of seldom physical objects observed in real world"?  Questions like "I do not know function of this object (picture) - which purpose does it have?"  In many cases I suppose these question could have civil engineering or handcraft i.e. cultural/historical background. In second case "SE history" might be okay. For first case, I do not know.

For example, this question might be offtopic. But where it is not?


$("button").click(function() {  if ($("#showHideButton").val() == "Read More2")   $("#showHideButton").val(function(){     return "Read Less"  });});   I'm trying to get a button to toggle values.

I want to create a toggle button in html using css. I want it so that when you click on it  , it stays pushed in and than when you click it on it again it pops out.   If theres no way of doing it just using css. Is there a way to do it using jQuery?


There is over 1 million kelp in my 1.15 server right now and i need to be able to remove them without opening the server for obvious reasons.

Basically, I acidentally spawned too many ArmorStands due to a wrong code writing , resulting in the game crashing, and wanted to know how to delete those armorstands from the World save folder. They hava names and I belive they also have a scoreboard set, if that helps.   I have already tried to open the world but it crashes, I tried to open a server (Since it worked the last time I tried it) and killing it all from the console but, different from the last time, it crashed before killing them and now I just tried MCedit but it crashes as well.


As mentioned in a , the major changes to QGIS 3.0 are:   Updating Qt4 to Qt5 Updating PyQt4 to PyQt5 Updating Python 2.7 to Python 3 Improving the QGIS API   Also, a couple of years ago,  seemed to have did some work on  back in 2015:     Multithreading execution. Multithreading execution of Processing algorithms was implemented as part of the Google Summer of Code this year. We collaborated in mentoring that work, but still some work has to be done before the code is ready to be merged. We have already started reviewing the code and adapting it with the goal of having this important functionality ready before QGIS 3.0 is released,, and we hope to have it ready for testing soon.     Will core functionality in QGIS 3.0 finally exploit multi-threading?

After reading , I was wondering if QGIS 2.6 will include this when running various processes. I checked online and I could only find that multi-threaded rendering was introduced to QGIS 2.4 (I assume it will again be available in 2.6). Now maps can be redrawn very quickly especially when dealing with large datasets.  I read that it's fairly difficult to include multi-threading to core functionality and that users are advised to manipulate Python code in order to achieve this, such as in .  I also checked the  but it has been closed for 9 months now by Tim Sutton with the last comment being:     "I'm closing this out - Martin Dobias has an implementation in a branch which will be merged post QGIS 2.2"   Will some functions in QGIS 2.6 exploit multi-threading (or will it again be focused on rendering) and if not, will that change at QGIS 3.0?


For the past few days I've noticed that some icons in   the Hot Network Questions on the right side of my browser window, and the "A list of all Stack Exchange sites" dropdown in the menu bar   have been incorrect, and that they are incorrect by exactly one index in the alphabetical list of the URLs (not the names) of the SE sites.  Here's one example of problem #1 from a few minutes ago on money.:     The top link is to a question on workplace., but the icon is for worldbuilding.. The second icon is fine. The third link is to a question on unix., but the icon is for ux..  The fourth icon is fine. The last link is to a question on money., but the icon is for movies..   As for problem #2, right now on stackoverflow.com here's what part of my dropdown looks like:    I don't know what all of these icons are, but I don't think any of them are correct.  The icon for tex. is from tor., workplace.'s is from worldbuilding. again, tor.'s is from travel., travel.'s is from tridion., tridion.'s is from ukrainian., etc.  Note that this does not always happen.  Sometimes all the icons are fine both in Hot Network Questions and in the dropdown.  Sometimes only some are wrong.  Also note that I'm behind a firewall that occasionally causes problems when loading things over HTTPS.  But I've not seen this particular problem behind this firewall before.

Self descript. I know it's already been asked  and . But apparently it's still an issue. This only started happening to me this week that I've noticed. Per the comments in the linked answer, a hard refresh should fix it but alas, it does not. Firefox 57.0. Works on SE but doesn't work on SO or many of the other sites I visit.   I disabled my add-ons and did a hard refresh but still to no avail. I've exited my browser cleared my temp stuffs as well.


html:

   javascript:    $(document).ready(function () {       $('.testSpanDiv').append('Hello');   }    $('#testSpan').on('click', function(){       $(this).parent().remove();   });   Event is not firing while giving a click to span element added dynamically. Event is firing if span element is statically added to the html. Can you give any suggestion over it.  I tried like below also, but not working.     $('#testSpan').on('click', '.testSpanDiv', function(){       $(this).parent().remove();   });

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I need the U values of Mann-Whitney test, but the wilcox.test in R outputs only W values. I do not think they are identical, so here is my question - how to convert W to U?

I've recently been reading about the Mann-Whitney U test. It turns out that to carry out this test in R you actually need to run a Wilcoxon test!  My question: is the W statistic of wilcox.test in R identical to the U statistic?


I've got a studying project about files managment system app in java(client-server- like google drive). One of the features is to open file. you click on a file and it should open. examples of files, doc,exe,txt,jpg.  My question is how do I do it in java? I know how to read/write from txt. but I need a generic code for all kinds of files..

I am displaying a list of files; i.e. xls, doc, pdf, odt etc., in my Java application (Eclipse RCP). When the user clicks on the file, I want to launch the appropriate  (according to what the OS thinks) native application, just like it happens in Windows Explorer or the Finder.  And while I am here: It would be nice to also display the same icons that Finder or Explorer use for the different file types.  Is there a library or Eclipse plugin for this?


I am unable to understand how the statement below gets this answer? Question:  >>>a=[1,2,3,4,5]  >>>a[3:1] >>>[]  >>>a[3:1:-1] >>>[4, 3]   Please explain to me why did I get this output?

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


Concentrating a lot of matter in one place will make a black hole, not a wormhole. A wormhole would change the topology of spacetime. Does General Relativity allow this? I know there are wormhole solutions to GR field equations, but they are static solutions. Is there a time evolving solution to the GR equations in which a flat region of spacetime transforms into a wormhole geometry/topology due to an appropriate inflow of matter and energy and negative energy? What determines where the other mouth of the wormhole forms?

I know there are solutions to Einstein's field equations that give a wormhole geometry. But they are time independent. They are static. Is there a process where empty flat spacetime can evolve into a wormhole by an appropriate flow of matter and energy and negative energy?   If so, it would change the topology of spacetime. Does General Relativity permit this? How would a hole in spacetime form? What determines where the other mouth of the wormhole would be located?


How could light from a TV screen refract when viewed through a helmet's  transparent visor?

I recently bought a few pieces of linearly polarized film (the one intended for smartphone LCD screens). At first I was confused because I could not make the polarizers work as they should - no matter, how I combined and rotated them, they did not block any light. All I got was a rainbow-kid effects.  I knew that the polarizers have protective plastic films on both sides of them, but it did not occur to me that these films might somehow interfere. After all, it's just a usual plastic film, nothing more.  To my surprise, after I removed the plastic films from the polarizers, they started to work! Then I tried various experiments with multiple kinds of transparent plastic items I had in my house and was dumbfounded. Almost every piece of plastic somehow interfered with the polarizers when the plastic in question was put in between. Some pieces of plastic showed only rainbow effects (I later found out that these rainbow effects indicate the stress of the plastic). I guess, that's completely normal and expected from everyday plastic when put between two polarizers.   But then some transparent plastic bags seemed to interfere with the polarization, so I had to rotate the plastic item about 45 degrees to get the polarizers work again. On the other hand, when I put a piece of cast acrylic sheet between the polarizers, it did not have any effect at all, like there's nothing between the polarizers - no even the stress rainbow effect I saw for other plastics.  How does it happen that there are so many transparent plastic items (including the plastic film used to protect the polarizers themselves) that happen to affect polarizers and either cancel their effect completely or have to be rotated 45 degrees to prevent the interference?  Does this mean that many everyday plastic materials are somehow polarized? Is this intentional or a side effect of some special plastic manufacturing process or materials? And how is acrylic special, that it behaves just like thin air between polarizers?


In set theory one often uses $\notin$ as with a slash through $\in$. How can I produce a similar slash through $\eta$?

I want to negate the symbol whose code is \models (this would be specific to Formal Logic). How can I do that? I tried a number of combination, but didn't find how this could be done. I tried \neqmodels, \nemodels, \notmodels, \nmodels  but all of them are wrong.  Is there a general way to negate symbols?


Can anyone please tell me how to hide admin account from the welcome screen without disabling it?  The method that uses the SpecialAccounts registry key does disable the account, so you can no longer enter the admin password to run elevated tasks from a limited account.  The solution should be usable by Home editions of Windows, so if it requires a group-policy, please also include the registry entry that the group-policy editor alters.

I have multiple accounts on my Windows 7 system. Sevral of these are for services, rather than users, yet they still show on the Windows 7 Login screen.  Is it possible NOT to display these non-user accounts on the login screen?


I have a question about sense verbs used in the progressive form, namely "hearing" and "seeing" in the contexts like the ones presented in the attached images (the underscored fragments). Is there any way to explain such a usage? I know that neither of them can be accounted for by the special meanings depicted in Swan's PEU or some dictionaries ("hearing things" - to hear sounds that are not real or "seeing someone" - to have an appointment). So, is it just an emphasis on the emotions of a speaker (surprise/disappointment) or the immediacy of an action? I presume that this usage is quite widespread because I've heard similar constructions in television serials/movies and I've seen them in other comics.

Many grammar books claim that ‘see’, ‘hear’, ‘taste’, ‘smell’, ‘feel’ are verbs that aren’t used in continuous forms, and yet, we do hear and see it quite often used by native speakers. For instance, read the title of this article:   The average complainer tells nine or more others about his unhappy experience. So successfully resolving a complaint is not only likely to generate increased business from the complainer, but also to restore nine or more potentially lost opportunities with other customers or prospects. The point is, if you're not hearing any complaints this might be a reason to worry, rather than to congratulate yourself.  I myself would say "I'm hearing more and more people pronounce this word this way" just as much as I would say "I hear more and more people..." Your thoughts, native speakers? Does using the continuous form of this verb feel odd to you?


I'm using the mathpazo package so I can set arbitrarily large font sizes for a poster.  I set my font sizes in the preamble as such:  \renewcommand{\normalsize}{\fontsize{36pt}{48pt}\selectfont} \renewcommand{\large}{\fontsize{64pt}{100pt}\selectfont}   But when I use \large, the line space is 48pt not 100pt as it should be (note that 100pt is not the actual value I want on my poster, this is just for demonstration purposes here).  If I change the line space value of \normalsize to 100pt, then when I use \large the line space is 100pt.  Complete code:  \documentclass[letterpaper]{article}  \usepackage[utf8]{inputenc}  \usepackage[letterpaper,top=2cm,bottom=2cm,right=2cm,left=2cm]{geometry} \pagenumbering{gobble} \setlength{\parindent}{0cm} \linespread{1}  \usepackage{mathpazo} \renewcommand{\normalsize}{\fontsize{36pt}{48pt}\selectfont} \renewcommand{\large}{\fontsize{64pt}{100pt}\selectfont}  \begin{document}  test 1 test 2 test 3 test 4 test 5 test 6 test 7 test 8 test 9  {\large test 1 test 2 test 3 test 4 test 5 test 6 test 7 test 8 test 9}  \end{document}   Resulting document:    But if I use:  \renewcommand{\normalsize}{\fontsize{36pt}{100pt}\selectfont} \renewcommand{\large}{\fontsize{64pt}{100pt}\selectfont}   I get:    Hmmm...

If I type something like this:  {\itshape\LARGE   Dunt venim dolorerosto do odit   ametum vulla conum dolore   conulput in vero od el   Dunt venim dolorerosto do odit   ametum vulla conum dolore   conulput in vero od el }   it results in a block of 4 lines with narrow spacing between the 1st and 2nd line and between the 3rd and 4th line. Line spacing between the 2nd and 3rd line is normal.  I can't fully explaing it to myself so I am looking for a short description for this behaviour. I know for example that with a \par at the end of the text (inside the group), the calculation would correct. But I have no idea why...


I've seen a lot of answers pertaining to grid elements, but I would like to center a grid container horizontally. Here's a snippet of the code I have right now.   .htable {   grid-row: 1 / 2;   grid-column: 2 / 3; }  .hlines {   grid-row: 1 / 2;   grid-column: 3 / 4; }  results[type='table'] {   grid-row: 2 / 3;   grid-column: 2 / 3; }  results[type='lines'] {   grid-row: 2 / 3;   grid-column: 3 / 4; }  form {   grid-row: 1 / 3;   grid-column: 1 / 2; }  content {   display: grid;   grid-template-rows: 5vw 85vw;   grid-template-columns: 20vw 35vw 35vw;   margin: auto; } <content>   <form>
     <uinput type='pulse'>       pulse:       <input type='number' class='pulse' min='2' maxlength='2' oninput='...'>     </uinput>

     <uinput type='cpulse'>       counterpulse:       <input type='number' class='cpulse' min='2' maxlength='2' oninput='...'>

     </uinput>   </form>

table
   <results type='table'>     <tableWrap>

              </tableWrap>   </results>
line diagram
   <results type='lines'>     <linesWrap>       <canvas class='lines' width=500px></canvas>     </linesWrap>   </results> </content>    I hope that's all the code that's needed so there isn't a need to comb through my messy code. Again, I'd like to center the grid container (as in the content element). Full source code , if needed.

How can I horizontally center a
 within another
 using CSS?

Foo foo


Something I wanted to ask before but always forgot. When downloading Ubuntu, the donation page pops-up. The only way to donate is via paypal. I do not have a paypal account any-more (closed it after bad experiences). Please, provide a means to donate by credit card.  Thanks

When I wanted to download Ubuntu 12.10 from ubuntu.com, I was asked to make a donation. However, there is only a PayPal option to make the payment. But I don't use PayPal. Is there any other option to make the payment?


As of December 2017, the largest known prime number was the Mersenne prime $2^{77232917} – 1$.  For such a large Mersenne prime, what are the techniques available for one to verify that it is in fact a prime?  Is it simply a matter of brute force checking, or are there other more elegant techniques available?

I am a software engineer but try to keep up with maths as I really enjoyed the subject at school. I just saw a great TED talk:   The talk states that the current largest known prime is $2^{57885161}-1$  This got me thinking - how does one actually prove whether a number this large is prime or not?  Is it just done by brute force via a computer algorithm or are there any well known mathematical techniques for doing so?  I would be really grateful for any pointers as I am eager to learn about these techniques (if they exist).


What will be the last three digits of the number $17^{256}$?   This question really intrigued me. First I thought that binomial theorem would help. But miserably failed. The given answer is 681. Please help!

What is the shortest way to compute the last 3 digits of $17^{256}$ ?  My solution: \begin{align} 17^{256} &=289^{128} \\ &=(290 - 1)^{128}\\ &=\binom{128}{0}290^{128} -  ... +\binom{128}{126}290^2 - \binom{128}{127}290 + \binom{128}{128} \end{align}  Computed the last 3 terms whose last 3 digits gave the last 3 digits of $17^{256}$.  Is there any shorter method to do this(which requires much less computation) ?


Is it possible to create a red/blue 3d effect in LaTeX using a preexisting package? If not, would anybody have any insight into how to go about this?  I am planning to make a beamer presentation on 3d effects, and the ability to have a 3d(even if it is gimickey) would be fun.  Link on red/blue 3d

Is it possible to create "real" 3D effects within a Beamer presentation using Stereoscopy (for 3D monitors)?  What I mean by that is:   Duplicate the slides left and right (for both eyes) Animations so that certain parts of the slide pop out of the screen, i.e. different translation in the left and right view Support for stereoscopic images, or even videos (with the multimedia or movie package). An example for a stereoscopic image:      Is there a package that allows creating these kinds of effects? Or a workaround with the normal Beamer package? Thanks.


I'm trying to install Ubuntu 13.04 alongside Windows 8 (to dual boot) on my new laptop.   Since there is already an EFI partition on the disk, I didn't create another one (as suggested in: ) and I selected /dev/sda3 as the device for boot loader installation. After the installation, ubuntu worked fine but I couldn't boot into Windows 8 (when I select the win8 in Grub screen it gives an error message). I restored computer to factory state using recovery and now trying to install ubuntu again.   Which partition should I choose for "Device for boot loader installation"? Thanks for the answers.  Harddisk is partitoned like this:

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I managed to put an image onto a glass pane (using UV-mapping and nodes). Following a tutorial on YouTube on acrylic glass, I was able to improved the pane (adding Fresnel to have the edges reflect). Unfortunately, I cannot seem to figure out how to add the image texture to the pane. The Fresnel is now blocking the port of the Mix Shader where my Image Texture used to go. This is my node-setup:  Using version 2.9.1.0 rendering with cycles.

I'm designing this animal-type creature, and want to add a transparent .png image to its face with the face features (object has a subsurf). On the left is the image with the features, on the right is the part of the object where I want it to be.    I tried to import the image as a plane, but matching the shape of the plane with the face didn't work, and the lines of the face left shadows on the head, and could be seen as a different object from some angles (although it's the closest I've gotten yet). It looked like this:    So , I tried selecting the faces of the head that the features should go over, and create a new material for it. Unfortunately, since the .png is transparent, the result produced was this:    (where it's impossible to tell the transparency from a black background default color, and where I wouldn't know where to start to adjust size and position).  I also tried UV mapping, but then the whole object became black with the features repeated all over.   Is it something I have to go into Nodes for? I'm kind of stuck here. Creating a new material and applying it is simple, but applying a material that is an image is a bit more complex it seems... Ideally, I would reproduce the same technique for the adhesive bandage on its arm (seen on the right of image 1).


I am using Putty to connect to Solaris machine (SunOS 5.11 11.3) from my Win10 PC (workplace mandates win, so it is necessary).  Despite trying different terminal definition strings and different keyboard settings in Putty I still get one or more of the next issues:   Home/End buttons either don't work at all (or just Home if 'rxvt' set as "The Home and End keys" in "Terminal->Keyboard") Or screen complaining that it cannot recognize TERM (trying to use 'linux' as terminal-type string in "Connection->Data"). And I absolutely need screen, yeah.   The closest I can get to something normal is:   Terminal->Keyboard:   The Home and End keys - rxvt The Function keys and keypad - Xterm R6  Connection->Data:   Terminal-type string - xterm-256color    But the 'End' button still doesn't work.  Who knows how to properly configure Putty in order for this buttons to work?  Maybe there is other freeware tool which I can use to achieve the desirable effect?

I connect to SunOS 5.11 11.3 machine via ssh using putty.  In terminal ctrl + arrow keys are not moving cursor to the previous/next words.  There is simple bash terminal on the Solaris machine.  Do you know how to fix this issue?  In the past I had  and already applied the solution (set terminal type string in putty to "linux"), but now I also want arrow keys working.


I am looking to this journal -International Journal of Information and Education Technology and it seems they need 700$ to get my work included ,once it is approved.But is it a scammy journal .Has anybody heard of this practice before FYI ,here is the link

A colleague and I recently submitted a paper to a journal with an impressive-sounding name, the "International Journal of Artificial Intelligence and Computational Research". According to ,      IJAICR is a referred [sic] journal in the field of computer science, artificial intelligence and soft computing methods.   It was accepted two days after we submitted it. That's too fast. We were suspicious. Although the journal said that all papers are peer-reviewed, we could not see how that was done in two days. Plus, we received no comments from the reviewers. Also, the submission guidelines didn't ask for a "blind" copy (without our names or any references to who we were).   But wait, there's more.  The acceptance letter asked us to send them US$300 to publish it. We did not. We've withdrawn our submission and will submit a new version of the paper to a more reputable journal in the coming months.  How might we make a better choice of respectable journals before we submit next time?


I am working on a problem that required finding $\int (-7-y)^2dy$. Instead of foiling it out, I just used u-substitution to find the antiderivative. ($u=-7-y; u'=-1$). I got an antiderivative of $\frac{-(-7-y)^3}{3}$. However, if you factor out this antiderivative you end up with a constant of $\frac {343}{3}$ that's not there if you foil then integrate. Why would the +c be defined for u-sub but not for foiling then integrating?

Question:  Is it possible to get multiple correct results when evaluating an indefinite integral?  If I use two different techniques to evaluate an integral, and I get two different answers, have I necessarily done something wrong?    Often, an indefinite integral can be evaluated using different techniques.  For example, an integrand might be simplified via partial fractions or other algebraic techniques before integration, or it might be amenable to a clever substitution.  These techniques give different results.  For example, looking over a few other questions on MSE:      From : evaluate $$ \int x(x^2+2)^4\,\mathrm{d}x. $$    Via the substitution $u = x^2+2$, this becomes $$ \int x(x^2+2)^4\,\mathrm{d}x       = \frac{1}{10}x^{10} + x^8 + 4x^6 + 8x^4 + 8x^2 + \frac{32}{5} + C.     $$ However, multiplying out the polynomial and integrating using the power rule gives $$ \int x(x^2+2)^4\,\mathrm{d}x       = \frac{1}{10}x^{10} + x^8 + 4x^6 + 8x^4 + 8x^2 + C    $$     From :  evaluate   $$ \int \frac{1-x}{(x+1)^2} \,\mathrm{d}x. $$    Simplifying the integrand using partial fractions then integrating gives $$ \int \frac{1-x}{(x+1)^2} \,\mathrm{d}x       = \frac{-2}{(x+1)} - \ln|x+1| + C.    $$ Via integration by parts, we get $$ \int \frac{1-x}{(x+1)^2} \,\mathrm{d}x       = \frac{x-1}{(x+1)} - \ln|x+1| + C.    $$     From : evaluate   $$ \int \frac {\tan(\pi x)\sec^2(\pi x)}2\,\mathrm{d}x. $$    Using the substitution $u = \sec(\pi x)$, this becomes $$ \int \frac {\tan(\pi x)\sec^2(\pi x)}2\,\mathrm{d}x       = \frac {\sec^2(\pi x)}{4\pi} + C.    $$ Using the substitution $u = \tan(\pi x)$, this becomes $$ \int \frac {\tan(\pi x)\sec^2(\pi x)}2\,\mathrm{d}x       = \frac {\tan^2(\pi x)}{4\pi} + C.    $$


I have a text file of this type, and I would look for any lines containing the string Validating Classification and then obtain uniquely the reported errors. I do not know the types of possible errors.  Input file:   201600415 10:40 Error Validating Classification: error1 201600415 10:41 Error Validating Classification: error1 201600415 10:42 Error Validating Classification: error2 201600415 10:43 Error Validating Classification: error3 201600415 10:44 Error Validating Classification: error3   Output file  201600415 10:40 Error Validating Classification: error1 201600415 10:42 Error Validating Classification: error2 201600415 10:43 Error Validating Classification: error3   Can I achieve this using grep, pipes and other commands?

Everywhere I see someone needing to get a sorted, unique list, they always pipe to sort | uniq. I've never seen any examples where someone uses sort -u instead. Why not? What's the difference, and why is it better to use uniq than the unique flag to sort?


I was wondering if you could cast shatter on the other side of a wall or on a point that you can't see. The spell description for shatter says that it is cast on a point that you choose. Other than that it does not say anything about how it's cast aside from it erupting from a point, so it seems there is no line involved. Would that also mean I can cast it in a room above me for example without even needing to see it? It says that if you cast an AOE spell it comes onto the near side of that obstruction, is that based on a line from where you cast or where the spell originates?

The rules on spellcasting contain the following section:   To target something [with a spell], you must have a clear path to it, so it can't be behind total cover. If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.  This section is not really clear to me. Should this mean that only non-transparent objects are  a problem in targeting, or that you have to have line of sight and line of effect as well? Also, can you prevent a wizard from casting spells by blinding her?


Show that $24 \mid (n - 1)n(n + 1)(n + 2)$ for all positive integers $n$.  Since $24 = 2^3 \cdot 3$ it follows that $(n - 1)n(n + 1)(n + 2)$ is divisible by $3$ since it contains the product of three consecutive numbers. If $n$ is odd then $n-1$ and $n+1$ are even and other one of them is divisible by $2$ and the other by $4$, thus the product is divisible by $2^3$. If $n$ is even then $n$ and $n+2$ are both even and similar reasoning follows that other one is divisible by $2$ and the other by $4$. Is this correct? For the odd case if I have that $n=1$ then $n-1=0$ and $n+1=2$, but neither one is divisible by $4$ here? Or does $0$ count as being divisible by $4$?

The problem is as stated in the title. I've tried factorization, but it doesn't seem to yield anything. Any help is greatly appreciated. Also please don't use modular arithmetic, thank you.


Does anyone know where I can find a good proof for the basis theorem of the cohomology ring of the Grassmannian, or give me a sketch of the proof?  I'm already familiar with basic Schubert Calculus.

Let $G(r, n)$ be the Grassmannian of the set of all $r$-planes in a $n$-dim vector space. How to show that the cohomology of a Grassmannian has a basis consisting of the equivalent classes represented by Schubert cycles? I am confused since I don't know how to compute the cohomology of a variety (how to construct the co-chain complex). I am really appreciate if you can compute the cohomology of, for example, $G(2,4)$ and show that it has a basis consisting of the equivalent classes represented by Schubert cycles.


Planning to use some sprites for a fan project but the sprites I want haven't been ripped yet; how can I extract them in a usable form?

I want to take the game Shaq Fu and change one of the sprites for my own. How would I go about doing it?


I am attempting to sort a List of fuses by the Designator property of the fuse.  The Fuse Model:  public class Fuse {     public string Designator { get; set; }      public string Rating { get; set; }      public string Type { get; set; } }   Example Data  This is an example of what a list of fuses would look like.    What I have tried:  fuses = fuses.OrderBy(f => f.Designator).ToList();   The above code sort of works, but it puts the F10 before F2. Does anyone know of a way to sort a List by the designator appropriately? I have read about natural sorting algorithms but not quite sure how to apply them correctly.  Any help would be greatly appreciated.  Thank you,

Anyone have a good resource or provide a sample of a natural order sort in C# for an FileInfo array?  I am implementing the IComparer interface in my sorts.


My code is returning gibberish(at least for me) and I don't know how to get it to work.  I've tried some different return configurations but none of them work the way I want it to.  class Main {   public static void main(String[] args) {     int[] reversing= {1,5,3,14,5,26,7,8,9,10,928,0};       System.out.println(reverse(reversing));   }   public static int[] reverse(int[] nums){     for(int i=0;i<nums.length;i++){       nums[i]=nums[nums.length-1];     }     return nums;   } }   The code is supposed to take an array of integers and reverse the numbers but instead it simply returns [I@5acf9800

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


If I am a normal user and I type  history   I get a set of commands typed by me in the terminal.  Now I make myself the sudo su (su stands for super-user here and not substitute user)  sudo su   I am typing again the history from the same terminal  history   I get a different set of commands which I had typed early.   I am working in a personal workstation.No one else handles the workstation. There are no users enrolled in the workstation other than me. Even if I obtain su (super-user) privileges, i am going to be using with those privileges also.  Hence I would like to obtain a consolidated system-wide same history irrespective of superuser or normal user.  How to achieve this?

Our small company runs an Ubuntu Server 11.10, to which a couple of people have SSH access. The actual terminals are sometimes used, too. How can we locally log all Bash commands run, along with user and time stamp?  We can assume that no-one is nefarious and actively trying to avoid the logging, but we'd still prefer the users not to have direct write-access to their log files. Simultaneous sessions must be handled correctly.


Is there an idiots guide available that can take me through installing Ubuntu onto my windows 8 laptop right from the start i.e. setting up my flash drive, FAT32, etc please?

I have been trying to install ubuntu (I tried 12.04LTS, 12.10, 12.10-secure-remix) using the wubi installer on Windows 8 and all the three times ran into the same problem showing some cannot find /ubuntu/winboot/wubildr when I tried to start ubuntu.  I tried to change the boot settings from UEFI to Legacy and then my laptop restarted and showed that "No operating System Found".  I then tried to install Ubuntu using a cd and after a lot of effort and using boot repair,etc. I landed into a new trouble. When I select UEFI on, the laptop loads Windows and windows too does not detect ubuntu. When I select Legacy mode, it starts ubuntu, shows me an option to start windows 8 but gives an error showing windows failed to load.  So in legacy mode, i am able to use only ubuntu and in UEFI mode, I am able to use only Win8. Please explain any process of starting windows in legacy mode (which I tried without any success) or starting ubuntu in UEFI mode.