Like the title suggests, I'm trying to print a map that uses OSM Stamen data from the OpenLayers plugin.  My map looks like this in QGIS:   And like this in the Print Composer:   But when I export the map to an image, it appears to be at a smaller zoom level.   Is there any way to actually make the map look like I'm desiring? I came across  thread, but it didn't lead me anywhere productive.

When I am creating a layer in QGIS the layer position/lines does not stay the same when I zoom in closer than, it seems like 1: 1000. I am adding 2 images to explain the problem. The moment I zoom in closer than 1: 1 000 then the original layer does not display correctly anymore.  Please, can you assist in this matter?


If $X_1, X_2 \sim \mathcal{N}(0,1)$ with correlation $\rho$, and $Y_1 = F_{X_1}(X_1)$ and $Y_2 = F_{X_2}(X_2)$, what is the correlation between $Y_1$ and $Y_2$? What is a proof that the correlation of $X_1, X_2$ is tightly coupled with the correlation of $Y_1, Y_2$, i.e. when the correlation in $X$ is low/high, so will be the correlation in $Y$?

Find the correlation coefficient $\rho_g$ of $(G(x), H(y))$ where $G(x),H(y)$ are marginal  C.D.Fs of $X,Y$ and $X,Y$ follow  bivariate normal distribution $\text{B.N.}(\mu_1,\mu_2,\sigma_1,\sigma_2,\rho)$. I am finding it difficult to calculate $E(G(x)H(y))$, otherwise I can find all the other terms. Please help! The answer given is $\frac{6}{\pi} \arcsin{\frac{\rho}{2}}$


The question i am going to ask is very much similar to this question-  But the problem here is, the radius of the spheres are too small (within 8 meter). I have used the Newton-Raphson method with Jackobian matrix to calculate a point which is exist in the intersection area of three spheres. I have the (lat,long) and a radius for three spheres and may be more. But every time I am getting a matrix which is not invertible. To apply NR method I've first convert the lat,long to x,y,z by this  lat = toRadians(latitude); lon = toRadians(longitude); x = earthRadius * cos(lat) * cos(lon); y= earthRadius * cos(lat) * sin(lon); z = earthRadius * sin(lat);   and used this as a center of a sphere and use r/1000 as radius (converted to KM) of that sphere. Algorithm starts with an initial point which i have considered the centroid. I guess it is for the Bad Starting Point. The radius is calculated form the signal strength of the different wi-fi access points(AP). The number of spheres are dependent on how many APs are available. Any advice would be helpful for me. EDIT The story repeated many times in stack exchange. I have 3 wi-fi APs with known (lat,lng) and using RSSI, I am calculating the distance (i.e. radius) in meter. Now I need to calculate the location of the mobile user. Main problem is the RSSI is fluctuating and in result estimated distance can not be estimated correctly. That's why the spheres are not always intersecting. But Newton-Raphson should try to find the intersection which is not happening. It throws an error that matrix is not invertible. Generated matrix may be or may not be square. If it is not square then used .

I need to find algorithm that can calculate centroid A (aka gravity center, geometric center, center of mass) from the figure where circles T1,T2,T3,T4,T5,..,Tn intersect AND length of line R from centroid to farthest corner of mentioned figure   Following information is given:   T1   Latitude    =   56.999883   Longitude   =   24.144473   Radius  =   943 T2   Latitude    =   57.005352   Longitude   =   24.151168   Radius  =   857 T3   Latitude    =   57.005352   Longitude   =   24.163356   Radius  =   714 T4   Latitude    =   56.999042   Longitude   =   24.168506   Radius  =   714 T5   Latitude    =   56.994226   Longitude   =   24.15709    Radius  =   771   Result should look like this:  A Latitude = XX.XXXXXXX    Longitude = XX.XXXXXXX  Radius = XX    As you probably already figured out, I am working on software that can find device location by closest Wifi Access Points or Mobile Base stations, as number of access points or base stations might change, I need an algorithm that can adapt to uncertain amount of points.  There are some similar questions  and , but none of them exactly answers to my question.


Consider the ordinary differential cquation $y^{\prime}=y(y-1)(y-2)$ Which of the following statements is true ? (a) If $y(0)=0.5$ then $y$ is decreasing (b) If $y(0)=1.2$ then $y$ is increasing (c) If $y(0)=2.5$ then $y$ is unbounded (d) If $y(0)<0$ then $y$ is bounded below I solve using separation  of variable and get implicit relation as $\frac{ y(y-1)}{(y-2)^2}= A e^ {2x} $ Now this becomes very difficult to apply condition and find the value of $A$  and check option is there easy method  to solve such questions ?

Consider the Ordinary Differential equation $y' = y(y-1)(y-2)$. Then from the different initial conditions, can we derive properties of the function $y$ ?  I thought of finding the solution to this differential equation, which I tried to use Partial fractions!, (any other easier or efficient method to solve this ODE?). After doing Partial fractions  I got  $0.5 \ln|y| - \ln|y-1| +0.5 \ln|y-2| = x + c$. Now if $y(0) = 0.5$, is the function $y$ decreasing?, well I thought of substituting value of $y(0)$ into the ode to get $y' = 0.5(0.5-1)(0.5-2)>0$, implying $y$ is decreasing (is this the correct way?). Also if $y(0) =1.2$ then using the above criteria I think $y$ is increasing? Also if $y(0) = 2.5$ then can we say anything about the boundedness of $y$ ? If $y(0)<0$, can we say $y$ is bounded below?.


Filesystem                   Size  Used Avail Use% Mounted on /dev/mapper/ubuntu--vg-root  292G  174G  103G  63% / none                         4.0K     0  4.0K   0% /sys/fs/cgroup udev                         902M  4.0K  902M   1% /dev tmpfs                        183M  1.3M  182M   1% /run none                         5.0M     0  5.0M   0% /run/lock none                         913M  156K  913M   1% /run/shm none                         100M   48K  100M   1% /run/user /dev/sda1                    236M  185M   39M  83% /boot   I use ubuntu 14.04

My /boot partition is nearly full and I get a warning every time I reboot my system. I already deleted old kernel packages (linux-headers...), actually I did that to install a newer kernel version that came with the automatic updates.  After installing that new version, the partition is nearly full again. So what else can I delete? Are there some other files associated to the old kernel images?  Here is a list of files that are on my /boot partition:  :~$ ls /boot/ abi-2.6.31-21-generic         lost+found abi-2.6.32-25-generic         memtest86+.bin abi-2.6.38-10-generic         memtest86+_multiboot.bin abi-2.6.38-11-generic         System.map-2.6.31-21-generic abi-2.6.38-12-generic         System.map-2.6.32-25-generic abi-2.6.38-8-generic          System.map-2.6.38-10-generic abi-3.0.0-12-generic          System.map-2.6.38-11-generic abi-3.0.0-13-generic          System.map-2.6.38-12-generic abi-3.0.0-14-generic          System.map-2.6.38-8-generic boot                          System.map-3.0.0-12-generic config-2.6.31-21-generic      System.map-3.0.0-13-generic config-2.6.32-25-generic      System.map-3.0.0-14-generic config-2.6.38-10-generic      vmcoreinfo-2.6.31-21-generic config-2.6.38-11-generic      vmcoreinfo-2.6.32-25-generic config-2.6.38-12-generic      vmcoreinfo-2.6.38-10-generic config-2.6.38-8-generic       vmcoreinfo-2.6.38-11-generic config-3.0.0-12-generic       vmcoreinfo-2.6.38-12-generic config-3.0.0-13-generic       vmcoreinfo-2.6.38-8-generic config-3.0.0-14-generic       vmcoreinfo-3.0.0-12-generic extlinux                      vmcoreinfo-3.0.0-13-generic grub                          vmcoreinfo-3.0.0-14-generic initrd.img-2.6.31-21-generic  vmlinuz-2.6.31-21-generic initrd.img-2.6.32-25-generic  vmlinuz-2.6.32-25-generic initrd.img-2.6.38-10-generic  vmlinuz-2.6.38-10-generic initrd.img-2.6.38-11-generic  vmlinuz-2.6.38-11-generic initrd.img-2.6.38-12-generic  vmlinuz-2.6.38-12-generic initrd.img-2.6.38-8-generic   vmlinuz-2.6.38-8-generic initrd.img-3.0.0-12-generic   vmlinuz-3.0.0-12-generic initrd.img-3.0.0-13-generic   vmlinuz-3.0.0-13-generic initrd.img-3.0.0-14-generic   vmlinuz-3.0.0-14-generic   Currently, I'm using the 3.0.0-14-generic kernel.


I've been programming, writing articles and presentations on LaTeX for couple of years; and made few tutorials about starting working with latex, adjusting properties to write on Georgian, drawing 2D/3D images with tikz...  Now, I want to start working with its core, writing commands, adjusting styles, without relying (so much) on prewritten packages.  Can anyone advise, how and from where can I start?

I noticed that there are a lot of "beginner" resources for LaTeX, lots of novice friendly tutorials etc.  Are there similar resources available for Plain TeX that are geared towards beginners?    Please note, prior to answering, that this question only relates to "Plain TeX".     To the best of my research, all of the TeX.SE existing answers setting out beginner resources deal only with "LaTeX".  The answer:   is great for people who want to learn LaTeX.  It does not however address those people (including me) who want to get started on learning Plain TeX.  The answers given so far are well thought out "Plain TeX" beginner resources.  Related:   Related:


I am working on a simple script tool that selects features from a .shp and creates a new output with only those features. Basically the user specifies(from a drop down list) the county and the preserve and the tool just does a select from a .shp with all the counties and the same for the preserves. I think the problem lies in my syntax, The tool runs without errors but gives me empty outputs. However if I test it without the user input and just put a county name and preserve name in the SQL statement it works which leads me to believe Im not telling the script to use the user input properly.  Here is the select part of my script:  #Variables/Arguments CNTY = "C:\\CRTOOL\\Data\\FL_Counties.shp" AP = "C:\\CRTOOL\\Data\\FL_AP.shp" Select_County = arcpy.GetParameterAsText(0) Select_AP = arcpy.GetParameterAsText(1)  # Select arcpy.Select_analysis(CNTY, "C:\\CRTOOL\\Data\\Your_County.shp", "\"NAME\" = '%Select_County%' ") # Select arcpy.Select_analysis(AP, "C:\\CRTOOL\\Data\\Your_AP.shp", "\"LONG_NAME\" = '%Select_AP%' ")   Here are tool parameters(I have tried them with and without the ' ' in the filter list:   UPDATE: WORKING SCRIPT  #Local Variables/Arguments CNTY = "C:\\CRTOOL\\Data\\FL_Counties.shp" AP = "C:\\CRTOOL\\Data\\FL_AP.shp" Select_County = arcpy.GetParameterAsText(0) Select_AP = arcpy.GetParameterAsText(1) where = '"NAME" = ' + "'%s'" %Select_County whereB = '"LONG_NAME" = ' + "'%s'" %Select_AP  # Process: Select arcpy.Select_analysis(CNTY, "C:\\CRTOOL\\Data\\Your_County.shp", where) # Process: Select arcpy.Select_analysis(AP, "C:\\CRTOOL\\Data\\Your_AP.shp", whereB )

I am trying to loop through a shapefile, selecting each feature in turn and copying it to a temporary shapefile to by included in a union analysis. I'm using a cursor to find the ID name for each feature which I'm setting to a varible 'Name'. Whenever I try to use this variable as part of the where clause in arcpy.Select_analysis I get an error:   ExecuteError: ERROR 999999: Error executing function. An invalid SQL statement was used. An invalid SQL statement was used. Failed to execute (Select).  The code I'm using is:  Name = 101 where = "\'\"StudyID\" = \\'"+str(Name)+"\\'\'" arcpy.Select_analysis("C:\\input.shp", "C:\\output.shp", where)   If I type it out without using the variables:  arcpy.Select_analysis("C:\\input.shp", "C:\\output.shp", '"StudyID" = \'101\'')   it works fine  What to I need to do to fit the variable into the sql statement?


i usually shot portraits with my 60D and tamron 17-50mm f2.8 using maximum resolution JPEG + RAW @ 5184 x 3456 pixels. after recent photoshoot, i tried to print an 8R using this particular setting and the result were dissapointing in my case (lack of details, seems stretched etc..) i wonder what is the proper way to print a large picture over 16x20" and 20x30"?   thanks

Creating high-quality photo prints using an ink jet printer is no trivial matter. Depending on the tonal range and color depth desired and the expected viewing platform, how you approach printing may differ. The choices you make when printing also affect how effectively you are using your printers capabilities, resolution, and ink.  So, how does one generate high quality photo prints using professional ink jet printers, such as  or , while maximizing the use of ink and the printers capabilities?     Empirical Studies:     (New!!)


Let $f,g$ positive measurable functions where $\mu$ is a positive measure. Is it true that $$\left(\int f d \mu\right)^2 + \left(\int g  d \mu\right)^2 \leq \left(\int \sqrt{f^2+g^2}d \mu\right)^2$$? By monotone convergence theorem, it suffices to prove this for simple functions. Write $$f= \sum_i a_i \chi_{E_i}, \quad g = \sum_j b_j \chi_{F_j}$$ with the sets on the indicators pairwise disjoint The LHS is $$\left(\sum_i a_i \mu(E_i)\right)^2 + \left(\sum_j \mu(F_j)\right)^2$$ The RHS is $$\left(\int \sqrt{\sum_i a_i^2 \chi_{E_i} + \sum_j b_j^2 \chi_{F_j}}d \mu\right)^2$$ How can I compare these two?

Let $(X, \mathfrak{B}, \mu)$ be a measurable space, possibly not $\sigma$-finite, and $f_1, \cdots, f_n \colon X\to (-\infty, +\infty)$ be integrable functions on $X$. Does $$(\int f_1d\mu)^2+\cdots+(\int f_nd\mu)^2\leq(\int \sqrt{f_1^2+\cdots+f_n^2}d\mu)^2$$ holds? (Since $\sqrt{f_1^2+\cdots+f_n^2}\leq |f_1|+\cdots+|f_n|$, note that integrand in RHS is integrable.)  My first attempt was to apply the Fubini's theorem and Cauchy-Schwarz to the LHS:  $\begin{align}(LHS)&=(\int f_1(x)d\mu(x))(\int f_1(y)d\mu(y))+\cdots+(\int f_n(x)d\mu(x))(\int f_n(y)d\mu(y))\\&=\int f_1(x)f_1(y)+\cdots+f_n(x)f_n(y) d(\mu\otimes\mu)(x,y)\\ &\leq\int \sqrt{f_1^2(x)+\cdots+f_n^2(x)}\sqrt{f_1^2(y)+\cdots+f_n^2(y)}d(\mu\otimes\mu)(x,y)\\&=(RHS)\end{align} $  However this approach is valid only if $X$ is $\sigma$-finite.  Note that the inequation is equivalent to the following: If $f\colon X\to \mathbb{R}^n$ is integrable, $$|\int f d\mu|\leq \int|f| d\mu$$


I want to offset the edges. An reference.gif is attached. I have done in other software. Can we offset the edges in that way.

How can I inset/extrude a face, so that the outer faces have the same width?    Any kind of help is appreciated


I want to know what are the best ways to evaluate $$\int _0^1\frac{\arctan \left(\frac{x^2-x}{x-2}\right)}{x}\:dx$$ It seems that it is equal to $\frac{G}{3}$ where $G$ is the Catalan's constant, I tried integration by parts and ended with $$-\int _0^1\frac{\ln \left(x\right)\left(2-4x+x^2\right)}{4-2x^3+2x^2-4x+x^4}\:dx$$ but this just looks complicated, I also tried to substitute the argument of the $\arctan$ and the sub $\frac{1-t}{1+t}$ but neither simplified things, can i please be given some hint on how to tackle this?. The original integral also equals $$-\frac{i}{2}\left(\int _0^1\frac{\ln \left(-2i+ix+x-x^2\right)}{x}\:dx-\int _0^1\frac{\ln \left(-2i+ix-x+x^2\right)}{x}\:dx\right)$$ But I'd prefer to avoid complex methods.

Some years ago, someone had shown me the formula (1). I have searched for its origin and for a proof. I wasn't able to get true origin of this formula but I was able to find out an elementary proof for it.  Since then, I'm interested in different approaches to find more formulae as (1).  What other formulas similar to ($1$) are known?  Two days ago, reading the book of Lewin "Polylogarithms and Associated Functions" I was able to find out formula (2).  $\displaystyle \dfrac{1}{3}C=\int_0^1 \dfrac{1}{x}\arctan\left(\dfrac{x(1-x)}{2-x}\right)dx\tag1$   $\displaystyle \dfrac{2}{5}C=\int_0^1 \dfrac{1}{x}\arctan\left(\dfrac{\sqrt{5}x(1-x)}{1+\sqrt{5}-\sqrt{5}x}\right)dx-\int_0^1 \dfrac{1}{x}\arctan\left(\dfrac{x(1-x)}{3+\sqrt{5}-x}\right)dx\tag2$   $C$ being the Catalan's constant.  I have a proof for both of these formulae.  My approach relies on the following identity:  For all real $x>1$,  $\displaystyle \int_0^1 \dfrac{1}{t} \arctan \left (\dfrac{t(1-t)}{\frac{x+1}{2}-t}\right) dt=\int_1^{\frac{\sqrt{x}+1}{\sqrt{x}-1}}\dfrac{\log(t)}{1+t^2}dt$


I have two partitions on my hard drive, one for Windows and one for linux. I would like to use VirtualBox in Linux to boot the Windows partition as a virtual machine. How can I acheive this?

Using Virtual Box, how can I install an OS to a secondary, physical disk, and boot it in both (at separate times) Virtual Box, and as a typical secondary OS install?


I am learner in verilog with less knowledge and trying to develop more understanding.I wrote a simple verilog code and synthesize and implement it. I do not have understanding of Look up tables. When I saw design summary, It's giving like: Device Utilization Summary              Number of 4 input LUTs       24(Used)         9,312(Available )      1%(Utilization)  What does it means? as it mention available no of 4 input LUTs are 9,312. Is it Device specification?  Thanks

I have gone through various sources... But I am not quite sure what it is.I want an and gate and the logical equivalent is two inputs feeding to one gate and for Y=AB' the logical equivalent is feeding to one not gate and one and gate. But it is the same LUT for both AND and Y=AB'. I think we store the values as desired in the LUT. Someone elaborate on this


Show that if $0 < x < 1$, then $$x-1 ≥ \ln(x) ≥ 1−\frac{1}{x}.$$   I know how to prove it using the MVT and I can prove it for $x> 1$ but I don't understand how to prove it for $x > 0$ .

One of fundamental inequalities on logarithm is: $$ 1 - \frac1x \leq \log x \leq x-1 \quad\text{for all $x > 0$},$$ which you may prefer write in the form of $$ \frac{x}{1+x} \leq \log{(1+x)} \leq x \quad\text{for all $x > -1$}.$$  The upper bound is very intuitive -- it's easy to derive from  as follows: $$ \log(1+x) = \sum_{i=1}^\infty (-1)^{n+1}\frac{x^n}{n} \leq (-1)^{1+1}\frac{x^1}{1} = x.$$  My question is: "what is the intuition behind the lower bound?" I know how to prove the lower bound of $\log (1+x)$ (maybe by checking the derivative of the function $f(x) = \frac{x}{1+x}-\log(1+x)$ and showing it's decreasing) but I'm curious how one can obtain this kind of lower bound. My ultimate goal is to come up with a new lower bound on some logarithm-related function, and I'd like to apply the intuition behind the standard logarithm lower-bound to my setting.


Suddently, Today one of my client asked me to setup google mail services for his business, currently he is using zoho mail and approx 5-6 user email working on zoho, now he purchased google mail services for 1 user and want to host only 1 email account from his zoho mail to google mail and for rest 5 users account he wants to be continue on zoho it self..  is there any possibilities to host both mx records of zoho and gmail for single domain.   any suggestion , it will be thankful.

I've seen articles about "different subdomains for different MX records".  But I want two records for the same domain, @abc.example for example.  Originally, I used Live Mail(MSN) to host my emails, and already have MX setup for it.  Now I want to use some of the Google App features, so I need to setup MX for Google Mail.  Can both of the two work together and well?


I've brought 2 New controller and both do the same the white light flashes but will not turn on, I'm assuming they are holding power as they are both New and genuine and the light flashes.  I'm not a computer person and it probably something silly but would appreciate some advise for my son. Thanks in advance Gav

I bluetooth paired my ps4 controller to my ps4 just fine. Then i deleted the bluetooth controller account (ps4 controller)off of my ps3. Now no matter what I do my controller won't work for the ps4. I click the home button and it blinks once then turns off. Someone please help me before I loose it.


I am developing an application in JSF using PrimeFaces. I have now come to a part where I want to provide uploading pictures (jpg, png, ...) for the user to use them in reports he writes.  I believe the normal way would to save them in some folder on the server. But I would prefer to save them to the database (MySQL or Oracle) as I find it easier to manage.  Do I have to face performance issues doing that? Or is this fully ok and just a matter of personal taste?

So I'm using an app that stores images heavily in the DB. What's your outlook on this? I'm more of a type to store the location in the filesystem, than store it directly in the DB.  What do you think are the pros/cons?


The fact that so many students confuse functional inverse notation $$f^{-1}(x)$$ with multiplicative inverse notation $$[f(x)]^{-1}$$ got me to thinking... does there exist a function whose inverse is its inverse? That is, is there a function $f:\mathbb R_+\mapsto \mathbb R_+$ whose functional inverse is also its multiplicative inverse, so that $$f^{-1}(x)=[f(x)]^{-1}, \space\space\space \forall x\in\mathbb R_+$$ Any ideas? I'll impose the restriction of continuity to deter nasty solutions.

Is there a function whose inverse is exactly the reciprocal of the function? That is $f^{-1} = \frac{1}{f}$.  We know that the inverse of a function is not necessarily equal to its reciprocal in general.


This was an exam question last year, and I was trying to figure out how to get the answer:  A small company is assigned the class C network 205.67.35.0. You need to divide this network to provide subnets for three departments using fixed-length subnetting. The departments are approximately the same size. Show the network and broadcast addresses for each subnet. Show the slash notation. How many hosts are on each subnet? Are the resulting subnets class C networks?  How would you go about doing this? How would you start it?

This is a  about IPv4 Subnets.      Related:               How does Subnetting Work, and How do you do it by hand or in your head?  Can someone explain both conceptually and with several examples? Server Fault gets lots of subnetting homework questions, so we could use an answer to point them to on Server Fault itself.   If I have a network, how do I figure out how to split it up? If I am given a netmask, how do I know what the network Range is for it? Sometimes there is a slash followed by a number, what is that number? Sometimes there is a subnet mask, but also a wildcard mask, they seem like the same thing but they are different? Someone mentioned something about knowing binary for this?


I managed to give a ring texture to an object, but I only want to restrict that texture to a part of an object, as highlighted in the picture.  How can I do that? I tried to mix in some color ramps as factors, min/max settings in the coordinate mappings but couldn't get it to work.

How do you add more than one material to a mesh?   I have tried adding two materials to the object, and then assigning one of the materials to a vertex-group, but I could not find a place to assign it.  I am making a striped bouncy ball that I want to deform, so adding a different material by separating the mesh into different objects would not be ideal.


Question When using cp command with environment variables, why pressing TAB for auto-complete doesn't work properly? Description I have a directory $HOME/Music; I want to copy a file from within this directory to the current directory. Therefore:  I Type cp $HOM and press TAB, so it reads cp $HOME ; There is an additional space after cp $HOME , therefore I delete it by Backspace and then type a slash:cp $HOME/; Now Press TAB creates cp \$HOME/ which has a spurious backslash at the beginning of $HOME. When writing further letters i.e. cp \$HOME/Mu for Music, TAB doesn't work for autocompletion.  OS: Ubuntu 20.04

I have this on the command line:    ln -sf $PWD/wine-   and then I hit Tab to complete the filename.  In earlier versions of Ubuntu, this worked just fine to complete the wine- filename (and as a side-effect $PWD would be expanded at that time).  But now it turns it in to  ln -sf \$PWD/wine-   which isn't what I meant at all and doesn't complete anything as the file does not literally start with $.  How do I get completion back to the less broken behaviour?  set tells me these are my current settings:  BASHOPTS=checkwinsize:cmdhist:expand_aliases:extquote:force_fignore:hostcomplete:interactive_comments:progcomp:promptvars:sourcepath SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor


Let ${a_1} > 0$ and ${a_n}$ be a sequence so that for any natural number  $a_{n+1} = 1/{a_n} + {a_n}$  Prove that sequence ${a_n}$ is unbounded.  How should I prove that? Can you give me any ideas ...

Does the recursive sequence $a_1 = 1, a_n = a_{n-1}+\frac{1}{a_{n-1}}$ converge?  Since the function $x+1/x$ is strictly monotonic increasing for all $x>1$, I don't think that the limit converges, but I'm not sure. Can anybody tell me whether the sequence is converging or not?


Prove that if $T:V \rightarrow U$ is an invertible linear transformation then the inverse $T^{-1}: U \rightarrow V$ is also linear So, $T$ is linear and thus $T(v_1+v_2) = T(v_1)+T(v_2)$ for all $v_1,v_2 \in V$. Also, $T$ is invertible and so we can write $T^{-1}T(v)=v$ for all $v \in V$. I'm a bit confused trying to put this all together, help appreciated!!

A question from the field of Linear Algebra. If I have a linear transformation $T$ that is one-to-one and onto, would that mean that the $T^{-1}$ will also be linear? If so, is there any general proof for it?  Thanks


I work on a document, and I would like to create, simultaneously, another document which has the 'doublespacing' tag on. Until now, every time I needed it, I just copied the TEX file to a "file-name-doublespace.tex", put on the doublespacing tag, and recompile.   Is there a way to automate this, so that on each compilation of the single file, I will get two files: original.pdf and original-doublespace.pdf which has the \doublespacing command?  Thanks.

I would like to control class options such as draft and geometry package's showframe from a Makefile.  Is there a way I can parameterise a document using LaTeX itself, or will I need to preprocess the document using sed from the Makefile?


It has always been a mystery to me as to why Eru didn't intervene to stop Melkor and Ungoliant from destroying the Two Trees.  I don't think it is plausible to say that he was not aware of what they were doing while they were doing it, that is to say that he could not see through the cloud of darkness that had been put up around the Two Trees while they were being destroyed. Moreover, as soon as he saw them approach the first tree he should have hit them both with huge bolts of lightning or some kind of power.  So, why didn't Eru stop Melkor and Ungoliant from destroying the Two Trees?  Was this ever discussed with Tolkien and did he offer an explanation for this?

Eru was infinitely more powerful than the Dark Lords, why didn't he stop them from trying to enslave the Free Peoples?


I'm writing an invoice with the dinbrief class (it occurs with letter too), using the invoice package and I want to include my signature as image. However, I'm running into mysterious errors even with a very simple example.  \documentclass[10pt,a4paper]{letter} \usepackage{german} \usepackage[utf8]{inputenc} \usepackage{graphicx} \usepackage{invoice} %\usepackage{graphicx}  \newcommand{\recipient}{%     Mr. Wong\\%     This street }  \address{%     Hey, it is\\%     me living here } \signature{My}  \begin{document}     \begin{letter}{\recipient}          \opening{Dear..}   Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.          \closing{Mit freundlichen Grüßen}      \end{letter} \end{document}   Using the code as above gives me a weird first page containing dates    Using \usepackage{graphix} as last import, gives an error  Missing \begin{document}. \NeedsTeXFormat{LaTeX2e}[.. I can't find file `keyval,graphics.sty'. RequirePackage{keyval,graphics}   What is wrong here and how am I supposed to include images?

I try to create an invoice with a logo in the background. But I get a strange result when I use graphicx and invoice in the same document. Here is my minimal example:  \documentclass{scrlttr2}  \usepackage[utf8]{inputenc} \usepackage[ngerman]{babel} \usepackage{graphicx} \usepackage{invoice}  \begin{document} % foobar \end{document}   It builds fine with pdflatex, but the resulting PDF file has this on it's first page:     [2007/09/09] [2010/03/01] [2010/12/02] [2010/09/13] [2007/11/11]   [2007/09/09] [2007/09/09] [2010/03/01] [2010/03/01] [2010/12/02]   [2007/09/09] [2007/09/09][2010/03/01] [2010/01/28] [2007/09/29]   [2007/10/02] [2007/11/11] [2009/07/12]   After this, a page break happens and the expected output begins. The footer is also on the first page (where the dates are) and the second page (the first with actual content) has no footer. Starting with the third page, everything seems fine.  Is this a bug in either invoice or graphicx?  Update: This only happens with pdflatex, the DVI output does not show the dates.


so I just wanted to know whether druids could transform into magical beats such as the Winter Wolf in 5e. Me and my friends recently started playing so it would be nice to know. Thanks.

Under Wild Shape it says "assume the shape of a beast" you have seen before. Does this mean they can only transform into creatures that have the beast type, such as bear, wolf, crocodile, etc.? Or can they turn into things with other types, like dragon, monstrosity, humanoid, fiend, etc.?


I tried all the possibility kindly let me know how resolve this error message and how to install git in my machine,  (personal)root@ubuntu:/home/shan/workspace/projects# apt-get -f install git-core Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  git-core : Depends: git (> 1:1.7.0.2) but it is not going to be installed  mysql-server-5.5 : Depends: mysql-server-core-5.5 (= 5.5.35-0ubuntu0.12.04.1) but 5.5.35-0ubuntu0.12.04.2 is to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


How to ask windows to search for files that not satisfy defined condition. For example I don't need files that has extension log.

I need to find and delete all files in subdirectories that are not .SQL files. I can't figure out how to search for <>.SQL or !.SQL in Windows Search.  Most of the solutions that I've seen here are to find specific extensions and do something with them. I'm looking for the opposite.


Recently, I've become interested in hyperoperations. I wondered what the equation y=x tetrated by x (x[4]x), which is the same as x pentated by 2 (x[5]2), would look like on a graph. To do this, though, would mean to tetrate a number by a non-integer value, and everywhere I've looked has just come up by saying that there just isn't any known way to compute this.   For a moment I tried to figure out a way but the properties of previous hyperoperations just don't carry over to tetration.  It's weird to me that this can be done with addition, multiplication, and exponentation but no further. Maybe we're just not used to looking at it in a certain way, I don't know, I'm not experienced in maths, I'm just curious.  Mainly, I just want to know if there is any/what research is being done on tetrating a number by a non-whole number/fraction. Or if there is any proposed way to calculate an answer to one of those problems.  Thanks in advance.

This question has been in my mind since high school.  We can get multiplication of natural numbers by repeated addition; equivalently, if we define $f$ recursively by $f(1)=m$ and $f(n+1)=f(n)+m$, then $f(n) = m \times n$.  Likewise, we get exponentiation by repeated multiplication. If $g(1)=m$ and $g(n+1)=mg(n)$, then $g(n) = m^n$.  In my high school mind it was natural to imagine a new function defined by repeated exponentiation: $h(1)=m$ and $h(n+1)=m^{h(n)}$.  These definitions only make sense for $n$ a natural number, but of course there are standard very mathematically satisfying ways to define multiplication and exponentiation by any real number. My question is this:  Can the function $h$ defined above also be extended in a natural way to $\mathbb{R}^{>0}$?  The question is in the spirit of seeking an extension of $f(n)=n!$ to $\mathbb{R}$ and arriving at $\Gamma(x)$.  Let me focus the question, and attempt to make precise what I mean by "in a natural way." Take $h(1)=2$ and $h(n+1)=2^{h(n)}$. $h$ is now defined on $\mathbb{N}$, and $h(2)=4$, $h(3)=16$, $h(4)=2^{16}=65,536$ etc. Is it possible to extend the domain of definition of $h$ to all positive reals in such a way that  a) The functional equation $h(x+1)=2^{h(x)}$ continues to be satisfied for all $x$ in the domain.  b) $h$ is $C^\infty$. (Analytic would be even better but this seems maybe too much to hope for?)  c) All $h$'s derivatives are monotone.  These requirements are my attempt to codify what would count as "natural." I am open to suggestions about what would be a better list of requirements.  If such a function exists, I would like to know how to construct it; if it doesn't, I would like to know why (i.e. outline of proof), and if relaxing some of the requirements (e.g. just the first derivative monotone) would make it possible.  (If the function exists, I am also interested in the questions, "is it unique?" "Could we add some natural requirements to make it unique?" But my main query is about existence.)


Official repo for MySQL8  not working.  How to add archive.ubuntu.com/ubuntu/pool/main/m/mysql-8.0/ to source list for Ubuntu 18.04 Bionic for setup MySQL8?  I'm trying to add next list to /etc/apt/sources.list.d/mysql.list  deb http://ua.archive.ubuntu.com/ubuntu/pool/main  bionic main deb-src http://ua.archive.ubuntu.com/ubuntu/pool/main bionic main   but it's not working

I'm using Ubuntu 19.04 and downloaded version 8.13 of MySQL APT config and ran these commands  wget https://dev.mysql.com/get/mysql-apt-config_0.8.13-1_all.deb dpkg -i mysql-apt-config_0.8.13-1_all.deb   I checked mysql.list using  vi /etc/apt/sources.list.d/mysql.list   and found version 8 is configured. And then I ran  apt install mysql-server apt-cache show mysql-server apt update   But still I can't install MySQL 8. APT is still pointing to 5.7.


I installed python 3.6.1. But then realized I don't have IDLE and can only access python via terminal by typing python. And the python version in the terminal is 2.7.12 not 3.6.1. I know Ubuntu comes with Python 2.7.12. But how come I can't use 3.6.1?

In Ubuntu, I tried to invoke IDLE  $ python3 -m idlelib ** IDLE can't import Tkinter. Your Python may not be configured for Tk. **   How shall I solve the problem?  I attempted to install idle by sudo apt-get install idle, but after that, running idle will invoke a shell for Python2.7 not for Python3.  Thanks.


My app should display a map in the first fragment. The app is organised by a Navigation Drawer. The map get's displayed without a problem, BUT it doesn't show the default zoom and location I provided.  The first error I got while creating the app was a NullPointerException. I know how to fix it, so I said that my map-fragment (which is mapFragment) is not null. The app now started working, but the code I wrote in my method onMapReady as well as the Button to get the current location and move the camera to this specific location didn't show/didn't work.  I also tried changing the code for the map but I always ended up in the same spot. If I don't write map!=null I get a NullPointerException. If I do write it, the app doesn't zoom in properly to the specific location.  In the Mainactivity:  @Override protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.activity_main);   SupportMapFragment mapFragment = (SupportMapFragment)   getSupportFragmentManager()           .findFragmentById(R.id.mapFragment);   if(mapFragment != null) {       mapFragment.getMapAsync(this);   } }   this is were I have to prevent the NullPointerException (mapFragment)    Here I set the default Location and zoom, which doesn't get applied to the map (while having the mapFragment!= null):  @Override public void onMapReady(GoogleMap googleMap) {      mMap = googleMap;      if(ContextCompat.checkSelfPermission(this,         Manifest.permission.ACCESS_FINE_LOCATION) ==         PackageManager.PERMISSION_GRANTED)     {         buildGoogleApiClient();          mMap.setMyLocationEnabled(true);     }      LatLng Luxembourg = new LatLng(49.611622, 6.131935);     mMap.moveCamera(CameraUpdateFactory.newLatLngZoom     (Luxembourg, 14)); }     this is the method to retrieve the user's current location (which also doesn't work while having mapFragment!= null):  @Override public void onLocationChanged(Location location) {     lastLocation = location;      if(currentUserLocationMarker != null)     {         currentUserLocationMarker.remove();     }      LatLng latLng = new LatLng(location.getLatitude(),      location.getLongitude());      MarkerOptions markerOptions = new MarkerOptions();     markerOptions.position(latLng);     markerOptions.title("current user location");     markerOptions.icon(BitmapDescriptorFactory.defaultMarker     (BitmapDescriptorFactory.HUE_RED));      currentUserLocationMarker = mMap.addMarker(markerOptions);      mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));     mMap.animateCamera(CameraUpdateFactory.zoomBy(14));      if(googleApiClient != null)     {         LocationServices.FusedLocationApi.removeLocationUpdates         (googleApiClient, this);     } }     this is the mapFragment itself:  <?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     xmlns:app="http://schemas.android.com/apk/res-auto">      <fragment         xmlns:android="http://schemas.android.com/apk/res/android"         xmlns:tools="http://schemas.android.com/tools"         android:id="@+id/mapFragment"         android:name="com.google.android.gms.maps.SupportMapFragment"         android:layout_width="match_parent"         android:layout_height="match_parent"         app:layout_constraintBottom_toBottomOf="parent"         app:layout_constraintEnd_toEndOf="parent"         app:layout_constraintStart_toStartOf="parent"         app:layout_constraintTop_toTopOf="parent"         tools:context="com.example.mapwithmarker.MapsMarkerActivity" /> </FrameLayout>     I expect the map to have the default location and zoom I provided as well as the button to move the map to the user's current location.

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?


I'm trying to write a merge method that takes three arrays and moves them into one. I'm quite new to java and the website where I'm submitting this code isn't very helpful with pointing out my error  static int[] mergeArrays(int[] a1, int[] a2, int[] a3) {  int[] answer = new int[a1.length + a2.length + a3.length]; int i,j,k; for (i = 0; i < a1.length; i++)     answer[i] = a1[i];  for (j = 0; j < a2.length; j++)     answer[i++] = a2[j];  for (k = 0; k < a3.length; k++)     answer[i++] = a3[k];  return answer; }

I need to concatenate two String arrays in Java.  void f(String[] first, String[] second) {     String[] both = ??? }   What is the easiest way to do this?


I'm providing a partial web hosting solution where my clients may upload and execute their own php scripts.  Besides the security routine I'll have to check (off topic here) I would like to know whether it is possible for me to prevent my clients to setup an "attack basement" in there?  I believe that I can't do much except making them sign some policy acceptance...  Also, since there's only a few IP shared by all the hosts, would there be a risk of everyone getting banned?

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


Is there a way to run a Java applet on Chrome or Firefox? I get the error message on the  that Java won't run on Chrome or Firefox anymore .  I have an old set of *.class files with an .html to run it, and I just want to be able to run this applet somehow. But how?

Why is the Java plugin (JRE) is disabled in Chrome? It is some security concern?  From official Java website:     Chrome no longer supports NPAPI (technology required for Java applets)   The Java plug-in for web browsers relies on the cross platform plugin architecture NPAPI,   which has been supported by all major web browsers for over a decade.   Google's Chrome version 45 (scheduled for release in September 2015) drops support   for NPAPI,   impacting plugins for Silverlight, Java, Facebook Video   and other similar NPAPI based plugins.   But anyone knows why? How it could be dangerous for Chrome user with latest version of Java JRE installed?


Let $f: R^n\to R\cup\{\infty\}$ to be a convex function. Let $f_{\epsilon}(x)=\frac{|x|^2}{2\epsilon}$. Show that:  $$\lim_{\epsilon\to 0}\inf_{x=y+z}f_{\epsilon}(y)+f(z) =f(x)$$  The $\leq$ part is trivial. But how to prove the other part?

Let $f(x)$ be a continuous function on $\mathbb{R}^n$, $f(x) \geqslant 0$ for any $x$. Define $$    f_{\alpha}(x) = \inf\limits_{y}\left( f(y) +\frac{|x-y|^2}{2\alpha} \right) $$ where $\alpha > 0$. How to show that $f_{\alpha}(x)$ is locally Lipschitz continuous and $f_{\alpha} \to f$ when $\alpha \to 0+0$ uniformly  on any compact $K$ in $\mathbb{R}^n$?


I know that \oint gives a closed line integral sign, but how do you make the same with a double integral instead? I tried \ooint and \oiint but neither worked.  EDIT: Also what would the corresponding commands for triple integrals be? And is there a way to do higher-order integrals (4,5,...)? Cheers!

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


Currently I wish to set up a dual boot configuration with Windows 10 as main and Ubuntu as my secondary OS. However, every time I try booting from the bootable Ubuntu USB (Corsair Voyager 32GB) I get the following error:  The same error happens on both the LTS version and the 15.10 version of Ubuntu. The USB boot has also been tested working on 2 other PCs (Not ASUS motherboards), which leads me to believe the issue is caused by not having any onboard or CPU graphics, but only dedicated GPU (GTX 980 Ti).  The error occurs right after pressing the "Install Ubuntu" option, and pressing any keys on the keyboard doesn't advance or provoke anything. It's just frozen. It's also worth noting that pressing the "Try Ubuntu without installing" option also triggers this error. So I'm not even able to boot on a pre-installed Ubuntu USB.  Has anyone got any ideas to what this could be? I have the latest BIOS version and I've also tried with defaulted F5 BIOS settings, same issue. I have no BIOS options pertaining to ACPI.  List of hardware, in case you need to know for troubleshooting:  CPU: Intel i7 5930k RAM: 4x 4GB Corsair Dominator Platinum DDR4 GPU: EVGA GTX 980 Ti Motherboard: Asus Rampage V Extreme PSU: Corsair AX1500i SSD: Samsung 950 512GB Pro M.2 NVMe SSD (Windows installation) SSD(2): OCZ Vertex 4 256GB SSD(3): OCZ Vertex 4 256GB (Ubuntu is going on this one) Monitor(1): Asus VG248QE 144hz 1080p Monitor(2): BenQ 2410t 120hz 1080p Headphones: Philips Fidelio X1 Mouse: Logitech G500s Keyboard: Corsair K70 RGB MX Brown USB: Corsair Voyager GT 3.0 32GB

I've created a 15.10 Ubuntu USB drive and booting off it with an ASUS Rampage IV Black Edition motherboard, I get:  Ignoring BGRT: invalid status 0 (expected 1)  and then nothing. I've become really frustrated trying to get a stable BIOS config with this motherboard (every boot produces an Overclocking failed! message and none of the even low-key default options avoid this message with an i7 3930K - this board rules as the hardest motherboard I have ever configured in the last 10 years!) and now it can't boot a vanilla 15.10 USB drive. I'd really value some help..  EDIT  I found the solution. See below.


What does this bless means in below hash value, and how to dereference it?  'limit' => bless( { 'days' => 2, 'minutes' => 0, 'months' => 0, 'nanoseconds' => 0, 'seconds' => 0 }),

I understand one uses the "bless" keyword in Perl inside a class's "new" method:  sub new {     my $self = bless { };     return $self; }       But what exactly is "bless" doing to that hash reference ?


I need to prove that $$1-\frac12+\frac13-\cdots-\frac1{200} = \frac1{101}+\frac1{102}+\cdots+\frac1{200}$$ I have tried to relate it to various expansions of Taylor Maclaurin series but to no avail. Please do not solve the problem. I need a hint.


Would I be able to use a Canon XL1s lens on a Canon EF-mount camera, such as the 5D, without an adapter? I'm looking to purchase one for my camera but I'm not sure if it will work.

I have a Canon XL1 interchangeable lens video camera. Can I use an adaptor to use its lenses with a DSLR or an SLR? I know about it using a smaller sensor and that it is closer to the sensor (as in ) but maybe there is an adaptor that gives it some space. I wouldn't mind if the picture is cropped. It's just so hard to sell this for nothing. The optics and glass used in this lens are top end.


I want the footer to stick to the bottom, but not being in front of other elements.  I've tried with position and bottom, but fixed is above the elements and absolute isnt' even at the bottom, it's only at the bottom of what you can see, but if you scroll down it stays there.      Copyright Duarte Arribas © 2019    footer{     display: block;     position: absolute; /*tried fixed also*/     background: #262626;     width: 100%;     height: 15%;     bottom:0;     color: #fff;     text-align: center; }

Given the following HTML:

     Copyright Foo web designs

    I would like #copyright to stick to the bottom of #container. Can I achieve this without using absolute positioning?


So I just finished the Star Wars series (again), and because I watched the original trilogy first, I ended with Revenge of the Sith, which brought a question to my mind.  Why in heaven's name did Yoda and Obi-Wan decide to bring Luke Skywalker back to his family on Tatooine?  I mean they were just talking about the fact that the twins need to be separated, they need to be kept hidden, and they need to disappear until the right time comes... Senator Bail Organa of Alderaan agreed to take Leia as both he and his wife had long wanted to adopt a girl. Since there is hardly any connection between the Skywalker family and the Senator of Alderaan, it makes sense that Leia would have been safe there.  And then suddenly Yoda tells Obi-Wan to take Luke to his family on Tatooine. I mean Anakin Skywalker, aka Darth Vader came from Tatooine. He was born and lived there for his first 10 years. He met Owen Lars and his girlfriend and future-wife Beru. His mother was buried right outside the doorway of the Larses' home. Why did Yoda and Obi-Wan think Luke would be safe and hidden somewhere so ingrained into Anakin's history?   I have read some other writings that say Darth Vader would never have wanted to return to, or even think about, Tatooine, where he spent the first ten years of his life as a slave. Also, since Padme was fitted-up to look like she had died still pregnant (as shown in the funeral scene in Revenge of the Sith), Vader and Sidious would not have known that the children survived, so they wouldn't have looked for Luke or Leia.   But seriously, there have got to be better places to hide someone. Sending Luke back to live with his family, and by extension, Anakin's family, right where Anakin's mother was buried (and we all know how much Ani loved his mom) seems like a huge risk...

In Episode II Anakin goes to the Lars homestead and meets his extended family. How would sending Luke there be "hidden" to Vader in any way? At least Leia had a random planet and family.


I can't find the starting points. Thank you for your help.

I need to prove that there is the following equality:  $$ \sum\limits_{k=0}^n {n-k \choose k} = F_{n} $$ where $F_{n}$ is a n-th Fibonacci number.  The problem seems easy but I can't find the way to prove it. Could you give me any hints? I'm looking for a combinatorial proof.


I am trying to get my .wav file to run from inside a .jar file once I have exported the program, and have researched extensively on the solution, but have found nothing that works.   Here is my current code:           Clip clip = AudioSystem.getClip();         clip.open(AudioSystem.getAudioInputStream(new File("soundfile.wav")));         clip.start();   What can I do to fix this?

In my application I load resources in this manner:  WinProcessor.class.getResource("repository").toString();   and this gives me:  file:/root/app/repository   (and I replace "file:" with empty string)   This works fine when I run my application from the IDE, but when I run the jar of my application:  java -jar app.jar   The path becomes:  jar:/root/app.jar!/repository   is there any way to solve this problem?  I'll use the "repository" dir name in order to create this:  ConfigurationContext ctx = (ConfigurationContext) ConfigurationContextFactory.createConfigurationContextFromFileSystem(repositoryString, null);   In the same manner, I'll get one file name (instead of a dir) and I'll use it this way:  System.setProperty("javax.net.ssl.trustStore", fileNameString)


How many ways are there to arrange five different letters so that none of them are in their previous positon?   If we have five different letters $a$, $b$, $c$, $d$ and $e$, we have to find the number of all possible ways of permutations such that $a$ is not in the 1st position, $b$ is not in the 2nd position, $c$ is not in the 3rd position; $d$ is not in the 4th position and $e$ is not in the 5th position of the word. I have tried the question using a brute force approach and found the answer to be 44. How can I solve this problem using combinatorial rules and theorems?

The recurrence relation for Derangement is as follows:  Let $D_n$ denote the number of derangements of a set $\{1,2,3,\ldots,n\}$. Then,  $$D_n=(n-1)D_{n-1}+(n-1)D_{n-2}.$$  Can someone give an intuitive explanation on how we come to find this result?


If so, in what conditions? Look at the . It's a duplicate hell. It can't be true that they were all posted in same minutes(I didn't check). There wasn't so many duplicates when I read the whole thread a while ago. What has happened? Are we supposed not to flag them?

Duplicate questions are "solved" — it's clear what to do with them, there're tools to deal with them... but what happens when two users post the same answer? This happens a fair bit, particularly on questions with simple answers ("Click this button"-type ones).  Do we upvote both answers, since they are both correct? Do we upvote the first one (although if the answers were posted within a few minutes of each other, after an hour it's impossible to tell as they both show up as "answered 1 hour ago")? Do we upvote the currently highest voted one? Do we upvote one and downvote the other? Do we flag one (seems a little excessive)? Something else?


Problem: Citation appearing in the list of figures.  Minimal Working Example:  \begin{figure}[H]     \centering     \includegraphics[scale=0.6]{phases-analyse-predictive.png}     \caption{Phases de l'Analyse prédictive \citep{Imanuel2014}}     \label{phases-analyse-predictive} \end{figure}   Current outcome:    Desired outcome:  The reference to appear in the  figure caption but not in the list of figures.

Sometimes I'd like to cite the reference in the caption of a graphic. But I want to avoid that this citation is displayed in the \listoffigures. How can I achieve that?  Fore example with this code:  \begin{figure}[htb] \centering \includegraphics{overview_pyramid.png} \caption{Overview pyramid \cite{LM2010}}\label{fg:overview_pyramid} \end{figure}


I came from a Windows background and just started using Ubuntu about two weeks ago.  I noticed something weird about the Unity window manager that just makes it feel quite unnatural:  For example, When I download a file in Firefox and click the button to open the folder in nautilus, it always opens minimized. I have to manually go to the launcher and click on the icon to see the window. The same thing happens when any program is started by another program.  I would expect to see the nautilus / any other window show up but instead just get into a state of confusion for a while until I realize that it's actually opened, but it's minimized.  Is there a way to allow windows opened by another program to not be minimized by default?

How can I make programs open in the foreground? Nautilus will open in the background, Remmina (the remote desktop program) also opens in the background. I have to click on the icon in the Launcher for it to come to the foreground. I would think any program that is invoked by any means would come to front, as it opens. It seems if one program invokes another, it will be in the background. If I click on any icons in the Launcher though, it will actually open in the foreground.


I have an associative array filled with more or less randomly mixed numeric and string keys, let's go with such example: $arr = array('third'=>321, 4=>1, 65=>6, 'first'=>63, 5=>88, 'second'=>0);  Now I'd like to sort it in such way:  Sort the array so the numeric keys would be first, and string keys after. The numeric values sholud be in specific order: 5, 4, 65 The string keys should be ordered by specific order as well: 'first', 'second', 'third' Output in this case should look like: array(5=>88, 4=>1, 65=>6, 'first'=>63, 'second'=>0, 'third'=>321) Each element might not be present at all in the original $arr, which might be additional problem...  My guess would be to split the array and make separate one with string keys, and one with numerc keys. Than sort each one and glue them together... But I do't know how to do it? Edit: Turned out to be a very poor idea, much better approach is in the answer below.

Is it possible in PHP to do something like this? How would you go about writing a function? Here is an example. The order is the most important thing.  $customer['address'] = '123 fake st'; $customer['name'] = 'Tim'; $customer['dob'] = '12/08/1986'; $customer['dontSortMe'] = 'this value doesnt need to be sorted';   And I'd like to do something like   $properOrderedArray = sortArrayByArray($customer, array('name', 'dob', 'address'));   Because at the end I use a foreach() and they're not in the right order (because I append the values to a string which needs to be in the correct order and I don't know in advance all of the array keys/values).  I've looked through PHP's internal array functions but it seems you can only sort alphabetically or numerically.


Is there a way to challenge "failed" audits? The system has failed me a few times already, where I thought the questions/answers were admissible, even if low quality:        So is there any way to challenge these?

I've run through Both SO and Meta searches for an answer, as well as reviewing the , and I cannot find a canonical process to challenge an audit failure.  I can find discussions of the single-choice "I Understand" topic that appear unresolved, in that no solution presently exists.  The particular question in point is .  Despite the number of up-votes, I feel that this quite clearly falls into a common closure category: "Here's my problem; how do I write the program?"  Compare this to   I also failed review on the first link I posted above, .  This looks like a case of code review, rather than SO.  I don't want to get rid of audits; I've learned good things from some of my failures, especially at the start.  However, in the past few weeks, a majority of my failures have been highly questionable, and I've drawn more than one suspension from those that are outright wrong by current standards.  If we have a challenge mechanism, please point me in the right direction.  Otherwise, it's simply not worth the annoyance any more, and I'll drop back to merely comments and answers.


My problem is this:  Given a necklace with length $N$, how many ways to color it using $2$ colors, such that any rotation should be counted only once?  For example, following $2$ necklaces should only be counted once.  What I tried was to reduce problem into something different, which is for every number $K | 1\leq K \leq N$, K is the number of black painted nodes. (I will call them nodes, also will use black-white as colors.). We can think the place between every adjacent pair of black nodes as a box, and think every edge as a bead. With this idea, the problem reduces to;  How many ways to put $N$ beads into $K$ boxes such that every box have at least one bead?  That can be calculated with the given formula: $\binom{N - 1}{K - 1}$ For example, we can show the necklaces on the top of this post as, $2 - 2 - 1$. We can see that every permutation of $2 - 2 - 1$ is actually representing the same necklace. So I'll instead use another example of $K = 4$ colors with $N = 11$. Let's just say $3 - 5 - 2 - 1$, well we can see that for example $5 - 2 - 1 - 3$ is still the same necklace. But $2 - 5 - 1 - 3$ is not the same necklace. I don't know how to calculate without this duplicates. I actually tried to derive something, that: $5 - 1 - 2 - 3$ $3 - 5 - 1 - 2$ $2 - 3 - 5 - 1$ $1 - 2 - 3 - 5$ With the power of guessing, I tried $\sum_{K = 1}^{N - 1}\frac{\binom{N - 1}{K - 1}}{K + 1}$, for $N = 11$, it results with $186 + 1$(all of the nodes are white -> $K = 0$) $+$ $1$(all of the nodes are black -> $K = N$) Edit: Small correction, (K + 1) on the above formula should be (K) instead. That is $\sum_{K = 1}^{N - 1}\frac{\binom{N - 1}{K - 1}}{K}$, which simpflies to $\frac{2^N - 2}{N}$ and works only when $N$ is prime. Also don't forget to add $2$ because of $K = 0$ and $K = N$. $= 188$, and according to my book, it's correct. But since I don't have any proof or anything, I don't know if it's correct or not. Though, for $N = 9$, according to the book, answer is $60$. But the formula gives $56.6$, with the +2, it's $= 58.6$. So I guess I'm still missing a point. Thank you for your answers in advance.

I was reading , and came across an equation which gives an expression for the number of necklaces of beads in two colors, with length n.  $Z_n = \dfrac{1}{n} \displaystyle \sum \limits_{d \mid n} \phi \left( d \right) 2^{n/d}$  The author says that this equality is well known, and cites Golomb and Riordan as examples.  However, I do not have access to these cited works.  I was curious, what is the proof of this equality?  Is it generalizable to necklaces with an arbitrary number of colors?  Related Questions (that do not answer my question explicitly):


Windows 8. (Not Windows 8.1)  I have Windows Update set to check for updates but not install them automatically. I get nearly daily notifications from Windows Update to install Defender updates. Can I set Defender to auto-download updates without allowing ALL Windows Updates to auto-install?  Note:  shows up as a similar question. It IS NOT A DUPLICATE because my question is about Win8, not Win7.

It looks like the Windows Defender in Windows 8 won't upgrade the signatures automatically, if Windows Update is set to "Notify, but don't install the upgrades".  Is my impression real? Is there is a fix?   I don't like automatic updates as I don't want to install useless updates like the ballot screen or something else, I want to choose.


Can one be "interested with" something?  As an example, I have a co-worker that asks:      "Are you interested with this position?"

Interested in/with the course   Which preposition is correct? in or with, or both.


Proof: For each $x,y∈\mathbb{N}$, if $x≤y$ and $y≤x$, then $x=y$  By definition of order, $x≤y$ if and only if $x<y$ or $x=y$  By definition of order, $x<y$ if there exist a $K∈\mathbb{N}$ such that $y=x+K$  and similarly the same for $y≤x$ is $y<x$ or $y=x$  $y<x$ is $x=y+M$ for some $M∈\mathbb{N}$.  now from here I'm having trouble seeing exactly where I need to go to actually prove $x=y$  I would assume I could do this inductively but I'm having trouble setting it up.

I'm having trouble deriving the following fact from the basic properties of $+_{\mathbb{N}}$ and the definition:  Definition. $\forall n, m \in \mathbb{N}: (n \geq m) \leftrightarrow (\exists a \in \mathbb{N}): n = m + a$. Fact. $\forall a, b \in \mathbb{N}: (a \geq b ~\land~ b \geq a) \rightarrow a = b$.  I've tried several different strategies, but none works. I think the fact that 0 isn't the successor of any natural number is the key both in the base case and the inductive step, but I keep going in circles trying to make use of that (and other basic facts about addition on $\mathbb{N}$). I would show you my notes, but there is really nothing of substance in them. I've made almost no progress since yesterday.


It seems widely stated, but not thoroughly explained, that Dark Matter is not normal matter as we understand it.  "Consistency with other observations indicates that the vast majority of dark matter in the universe cannot be baryons, and is thus not formed out of atoms."  How can we presume to know this? Our best evidence for such dark matter is the rotational speeds of galaxies. It sounds like we can measure/approximate the gas density and stellar masses somehow, yet I don't understand how we can account for things like planets, asteroids, black holes without accretion disks, and other things that have mass but don't glow. How is it we dismiss these explanations for it, and jump right to WIMPs and other exotic explanations?

There's more gravitational force in our galaxy (and others) than can be explained by counting stars made of ordinary matter. So why not lots of dark planetary systems (i.e., without stars) made of ordinary matter? Why must we assume some undiscovered and unexplained form of matter?


Okay this is kind of hard to explain but I'll try my best.  I'm creating a program that reads from a .data file, saves each line of the file into an array list, then the user specifies the building and room number to look for, the program then searches through the whole array list (couple thousand lines) for matches, then with those matches calculates how often those rooms are used using some of the data obtained from the data file.   Now, the problem is that I can get up to the program searching through the array list, but it seems to be doing something incorrectly.    String buildingNum = jTextField2.getText(); String roomNum = jTextField1.getText();  int strDuration = 0; int totalDuration = 0; int meetings = 0;  for (int x = 0; x < Global.globalLength; x++) {     if ((buildingNum != "XXXX") && (list.get(x).building != "XXXX") && (list.get(x).room != "XXXX") && (roomNum != "XXXX")) {         int intBuildingNum = Integer.parseInt(buildingNum);         int intRoomNum = Integer.parseInt(roomNum);         int listBuildingNum = Integer.parseInt(list.get(x).building);         int listRoomNum = Integer.parseInt(list.get(x).room);         if (listBuildingNum == intBuildingNum) {             System.out.println("Second STEP WOO");             if (listRoomNum == intRoomNum) {                 strDuration = Integer.parseInt(list.get(x).duration);                 meetings = list.get(x).days.length();                 totalDuration = totalDuration + (meetings * strDuration);                 System.out.println(strDuration + " and " + meetings);                 System.out.println(" and " + totalDuration);             }         }     } }  int utilization = totalDuration / 50; jTextArea1.setText("The room utilization is: " + utilization);   In the data file, there are a few places in which data is entered as XXXXXXXXXXXX for whatever reason.  Because of this, when trying to convert said data into an integer there's a problem (for obvious reasons).  So to fix this, I made that odd if block right after the for loop so that the program would try not to do so. However, When running it, I am able to get the program to display the total duration a couple of times before it gives an error that says  Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "XXXX" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)   Which I THOUGHT I had fixed.  Can anyone see why it would still be trying to convert the XXXX into integers?

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 am not able to understand ls and cd behaviour in following case : Create directory a/b/c  $ mkdir a/b/c -p $ ls -lhRai .: total 324K 24512531 drwxrwxr-x  3 mayank mayank 312K May 22 16:23 . 24380771 drwxr-xr-x 34 mayank mayank 4.0K May 22 15:14 .. 25690305 drwxrwxr-x  3 mayank mayank 4.0K May 22 16:23 a  ./a: total 324K 25690305 drwxrwxr-x 3 mayank mayank 4.0K May 22 16:23 . 24512531 drwxrwxr-x 3 mayank mayank 312K May 22 16:23 .. 25690306 drwxrwxr-x 3 mayank mayank 4.0K May 22 16:23 b  ./a/b: total 12K 25690306 drwxrwxr-x 3 mayank mayank 4.0K May 22 16:23 . 25690305 drwxrwxr-x 3 mayank mayank 4.0K May 22 16:23 .. 25690307 drwxrwxr-x 2 mayank mayank 4.0K May 22 16:23 c  ./a/b/c: total 8.0K 25690307 drwxrwxr-x 2 mayank mayank 4.0K May 22 16:23 . 25690306 drwxrwxr-x 3 mayank mayank 4.0K May 22 16:23 ..   cd to innermost directory c  $ cd a/b/c   from another terminal, remove directory a, i.e.  $ rm -rf a   but ls is still getting inode info  $ pwd /home/mayank/Tmp/a/b/c $ ls -lai . total 0 $ ls -laid . 25690307 drwxrwxr-x 0 mayank mayank 0 May 22 16:23 . $ ls -laid  25690307 drwxrwxr-x 0 mayank mayank 0 May 22 16:23 . $ ls -laid ../ 25690306 drwxrwxr-x 0 mayank mayank 0 May 22 16:24 ../ $ ls -laid ../.. 25690305 drwxrwxr-x 0 mayank mayank 0 May 22 16:24 ../.. $ ls -laid ../../.. 24512531 drwxrwxr-x 2 mayank mayank 319488 May 22 16:24 ../../..   offcourse cwd file in /proc of bash is pointing to deleted dir  $ ls -l /proc/$$/cwd lrwxrwxrwx 1 mayank mayank 0 May 22 16:32 /proc/13125/cwd -> /home/mayank/Tmp/a/b/c (deleted)   Also, not able to understand cd behaviour  $ cd .. cd: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory     $ ls -li total 0 $ ls -lid 25690306 drwxrwxr-x 0 mayank mayank 0 May 22 16:24 . $ pwd /home/mayank/Tmp/a/b/c/.. $ cd .. cd: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory $ pwd /home/mayank/Tmp/a/b/c/../.. $ ls -lhid 25690305 drwxrwxr-x 0 mayank mayank 0 May 22 16:24 . $ cd ..     Tmp:$ ls -lhtrai total 320K 24380771 drwxr-xr-x 34 mayank mayank 4.0K May 22 15:14 .. 24512531 drwxrwxr-x  2 mayank mayank 312K May 22 16:24 . Tmp:$ cd - bash: cd: /home/mayank/Tmp/a/b/c/../..: No such file or directory   cd was not able to get parent dir info in c b , but a

I have two shells open. The first is in directory A. In the second, I remove directory A, and then recreate it. When I go back to the first shell, and type ls, the output is:  ls: cannot open directory .: Stale file handle   Why? I thought the first shell (the one that remained open inside a non-existent directory) would "freeze" while waiting for the next command, and wouldn't have "realized" that the directory was deleted and recreated. Does the shell hold a "deeper" reference to its current working directory other than the string $PWD?


I'm trying to use the Finder to search my code base. For example I would like to find every files that ends with ".m" and contains "keyDown".  Finder does this, but in the Finder window showing the results, the full path can not be displayed individually on each line, but only if you click on the file. In this case it's displayed on a status bar on the bottom.  Is there a way with Finder, or possibly another tool, to display the full path for each file next to the filename ?

I often use SpotLight to find files in macOS Mojave.   However, many times there are multiple files with the same name.  Is there a way to display the full path for each file in the spotlight window where the found files are listed?


Is there a name for "sts", "sks" and "sps" sounds found in words like "tastes", "tasks", and "wasps"?  I seem to remember someone telling me the name for it.

While reading about diphthongs in a different question today, I noticed that while the word "diphthong" doesn't seem to contain any actual diphthongs, it does contain 3 sets of consonant groupings.  When I was younger, I used to think consonant groupings actually were called diphthongs. I know now that I was mistaken, but I do wonder - is there a single word that describes consonant groupings?  After doing some searching on Google, Wikipedia and this site, I'm unable to find a definitive answer besides "consonant cluster" or "consecutive consonant". Those terms may be the only accurate ones available, but I would be mildly disappointed.


I am trying to configure Wifi Direct to connect to a 4.1 Android Phone. What are the correct steps to setup and configure wifi Direct to connect to a Phone that supports the same feature.

I am an Ubuntu newbie. I have a HP DM1 laptop with Ralink RT5390 wifi card. It has the ability to connect on wifi direct with my Nexus 7 in Windows while using latest drivers located at Mediatek site. But I am unable to use wifi direct in Ubuntu. I found wpa2_supplicant supports this and installed the same, but still wifi direct is not functioning.  Can anyone help?


I'm looking for a word that means feeling both happy and sad at the same time. Here's a sentence I'd like to use it in:     "At least we got one vote," she said with a (word I'm looking for) smile.

Are there words or other phrases for "a bit sad" and "a bit happy"?  Thank you!  Edit:  I'm sorry for the confusion. I wanted at least two words: one for "a bit sad" and one for "a bit happy". Thanks anyway for the answers for mixed happy and mixed sad. I hope there will be other answers for the two distinct phrases. Thanks!


First of all, a screenshot storyboard:     I tried uploading a 5MB image just as an experiment. The pro API shouldn't mess this up, right? Why doesn't this work?

I was trying to upload a gif file (4MB) into a post. I get the following error:     For security reasons, framing is not allowed. Click OK to remove the frames.   See this gif screenshot (click  if it doesn't play):    Why I am getting this error? Is the size of the file a reason?  Same story is here, on meta, when trying to upload same file.


Quantum field for Klein-Gordon Equation is defined as $$\phi(x)=\int\frac{d^3k}{(2\pi)^3\sqrt{2\omega_k}}(a_k e^{-ikx}+a^{\dagger}_ke^{ikx})$$ Please forgive me for my slopiness here regarding the vector k in creation and annihilation operator. Now my question is I don't see the R.H.S of above equation as manifestly Lorentz invariant as following:   The 4-vector product in exponential is of course manifestly Lorentz invariant. But the issue is this term: $\int\frac{d^3k}{\sqrt{2\omega_k}}$ I know $\int\frac{d^3k}{2\omega_k}$ is manifestly Lorentz invariant because it can be written as $\int d^4k\hspace{3pt}\delta(k^2-m^2)\hspace{3pt}\theta(k^0)$. If I take $\phi(x)|0\rangle$ then it is manifestly Lorentz invariant because in my convention $a_k|0\rangle=\frac{1}{\sqrt{2\omega_k}}|k\rangle$.   So does this mean that $\phi(x)$ doesn't need to be manifestly Lorentz invariant cause if we're doing some observation ultimately we have to operate it on some state and that expression as seen above is manifestly Lorentz invariant.

When we canonically quantize the scalar field in QFT, we use a Lorentz invariant integration measure given by $$\widetilde{dk} \equiv \frac{d^3k}{(2\pi)^3 2\omega(\textbf{k})}.$$  How can I show that it is Lorentz invariant?


I have to insert a VLAN tag to an untagged incoming packet. In various Linux based network switches we have a provision to set the PVID of a port if the incoming packet is untagged. I am looking for something similar to that. Anyone know how ?

I'm trying to set up a system that joins an untagged Ethernet network to a TAP tunnel, adding a VLAN tag as the traffic moves to the tunnel.  So far I have:   eth0 - the physical Ethernet interface carrying untagged traffic. tap1 - the TAP tunnel interface. br0 - a bridge that contains tap1 (and some other physical interfaces)   I know I can add a VLAN tag on the Ethernet side by doing this:  $ ip link add link eth0 name eth0.5 type vlan id 5 $ brctl addif br0 eth0.5   But how can I do the reverse?  Edit I've figured out I can do this:  $ ip link add veth0 type veth peer name veth1 $ ip link add link veth0 name veth0.5 type vlan id 5 $ brctl addif br0 veth0.5 $ brctl addbr br1 $ brctl addif br1 eth0 $ brctl addif br1 veth1   I think this does what I want - it creates two bridges, with a virtual ethernet device connecting them, and adds/removes the VLAN tag as the traffic passes between the bridges.  Is there anything simpler?


which is correct?  How much IS a dozen of donuts?  OR How much are a dozen of donuts?

The word dozen is a collective noun, i.e., singular when we think of them as groups and plural when we think of the individuals acting within the whole. So we might say:     Talking about eggs: "A dozen is probably not enough."   Talking about a party with friends: "A dozen are coming over this afternoon."   So, a dozen roses would likely be considered singular (like a bouquet). We might say, "A dozen roses costs ten rupees," as per subject-verb agreement.   1) However, since we have six dozen, does the modification of the noun by a number change the subject to plural, resulting in cost? Or is it all moot because of the plural roses?  In American English, collective nouns tend to be singular while in British English they may be both. That said, I've seen the suggestion that cost be used, which would be straightforward to me if dozens (plural) were used. From an American perspective, I feel the subject should remain singular when modified by a number: "Three dozen is enough to feed an army," or "Two dozen pizzas is/are too much" (the be verb is interchangeable in the 2nd example).  2) Is sticking with singular in the case above purely my American usage side showing, or is it a shared phenomenon?   states:     When modified by a number, the plural is not inflected, that is, has no -s added.   3) (Main Question) Does this have any bearing on whether the subject is treated as a plural? That is, since a plural is not inflected, could the subject remain singular, or is this irrelevant?  Note this is , since that question is vague and about to be closed and my suggested edit, which is the basis of this question, was rejected.


I have two different ciphertexts $c_1$ and $c_2$, and two different public keys that share the same modulus such that $e_1 \neq e_2$ but $n_1 = n_2$.   What attack can I use to recover the private keys? Common modulus attack works only if $c_1 = c_2$, doesn't it?

I am struck with the following problem:  Let Alice, Bob, Chris and Eve communicate over a public network. They encrypt all messages they send using RSA system. Bob and Chris have the RSA modulus $n_B$ and $n_C$ respectively with $n_B$ = $n_C$ But different public encryption exponents: $e_B \neq e_C$. Suppose $\gcd(e_B, e_C)=1$, and that Alice sends the same secret message to Bob and Chris. Show how Eve can decipher the message.


One of the former student    One of the former students       Which one is correct, and why? Can any one explain it clearly?

Which of the following is correct?        Yesterday, I met one of my friends.   Yesterday, I met one of my friend.


I am having a hard time finding out how to install programs in Ubuntu in the right location. If I use Ubuntu Software Center to install a program that gets installed in its right place, but when I download a program manually in this case PhpStorm it went to the Downloads folder and when I ran the command  /home/shairyar/Downloads/PhpStorm-139.732/bin/phpstorm.sh   I assumed it would get installed in the directory where it is supposed to go.  After I ran the command phpstorm kicked off, I did the work I needed to do, and before shutting off the computer I thought of cleaning the Downloads folder. After deleting the phpstorm folder there I could no longer use the phpstorm shortcut I created.  So after restoring the deleted files, how do I move phpstorm to its right location? In future how do I make sure applications are installed to the right places?

How can I install applications like Google Chrome on Ubuntu?  Are there any commands to install an application?    Index of answers:


I am using an HP NoteBook 15-ay503tx. I have been facing this issue since 3 weeks ago.

I am attempting to install Ubuntu on a box which was previously running Windows 7.  I have also experienced the dreaded "Unable to install GRUB" error.  I am not attempting to dual boot. I have previously run a Windows boot disk and removed all existing partitions.  If I run the Ubuntu 12.04 install CD and click install after the config screens, I get the error   Executing 'grub-install /dev/sda' failed. This is a fatal error. (It is the same error as this question: )  All the questions I've read while looking for a solution are related to dual boot.  I'm not interested in dual boot, I'm after a clean out the box Ubuntu install. How can I achieve this?  (For my sanity, please use very simple instructions when responding. I don't claim to have any talent either for linux or as a sysadmin)    Additional details copied from comments dated: 2012-05-29 ~15:19Z  After booting from the CD, clicking Try Ubuntu, and then sudo fdisk /dev/sda I get fdisk: unable to seek on /dev/sda: Invalid argument  sudo fdisk /dev/sdb gives   Device contains neither a valid DOS partiion table, nor Sun, SGI or OSF disklabel.  Building a new DOS disklabel with disk identifier 0x15228d1d.  Changes will remain in memory only until you decide to write them.  After that of course, the previous content won't be recoverable.  Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite).  Command (m for help):   I should add the Live CD desktop is graphically bad. I've got missing parts of programs and the terminal occasionally reflects to the bottom of the screen. But I can't imagine this is related.


I upgraded my lubuntu 18.04 to the newest 18.10 version -- I started the upgrade in the terminal with sudo apt-get upgrade.  When I rebooted the only thing I got was an empty desktop with the new wallpaper. No icons, no task bar. Nothing. I can't even access the terminal with  CtrlAltt.

Since there are major differences between Lubuntu 18.04 LTS and Lubuntu 18.10 primarily involving the change from LXDE to LXQt is there any guidance available for those who wish to upgrade from 18.04 LTS to 18.10, as opposed to performing a clean installtion of 18.10?


I wondered if a continuous interval like $[0,1]^{\mathbb{R}}$ has countable or uncountable infinite elements.  So i looked for a bijective mapping and found following:  $f:\mathbb{N} \to ]0,1[^{\mathbb{R}}$  $f:x \mapsto \frac{x}{10^{\lfloor\log_{10}x\rfloor+1}}$  $f(1234) = 0.1234$  Therefore $[0,1]^{\mathbb{R}}$ should have countable infinite elements, shouldn't it?

Every real number in $[0,1]$ has a decimal expansion $0.d_1d_2d_3...$, so construct an infinite tree rooted at 0 where each node has branches leading to $\{0,1,2,3,4,5,6,7,8,9\} $, and let each path through the tree represent the successive decimal digits of a real number. To enumerate them, go through the tree breadth-first i.e. layer-by-layer.


I have a problem with install mysql_install_db.  When I call mysql_install_db I get this error:  [WARNING] mysql_install_db is deprecated. Please consider switching to mysqld --initialize 2016-10-10 16:06:57 [ERROR]   The data directory needs to be specified. root@furniture-ecommerce:~# mysqld --initialize 2016-10-10T16:13:24.343724Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2016-10-10T16:13:24.350429Z 0 [ERROR] --initialize specified but the data directory has files in it. Aborting. 2016-10-10T16:13:24.350786Z 0 [ERROR] Aborting   I deleted the directory /var/lib/mysql as here recommend -  but when I call mysqld --initialize then this error occurs:  mysqld: Can't create directory '/var/lib/mysql/' (Errcode: 13 -     Permission denied) 2016-10-10T16:23:29.515470Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2016-10-10T16:23:29.519420Z 0 [ERROR] Aborting   Can you help me with it?

I was following this tutorial:    So far, I installed mysql-server mysql-client libmysqlclient-dev, and I was suppose to tell MySQL to create its database directory structure where it will store its information using sudo mysql_install_db.  $ sudo mysql_install_db  [WARNING] mysql_install_db is deprecated. Please consider switching to mysqld --initialize [ERROR]   The data directory needs to be specified.   I thought running mysqld --initialize would solve the issue:  $ mysqld --initialize   mysqld: Can't create directory '/var/lib/mysql/' (Errcode: 17 - File exists) [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). [ERROR] Aborting   How do I tell MySQL to create its database directory structure where it will store its information?


One of Yoda's objections to training Luke was that he was too old.  Also, with the limited time available, by the time Luke first faced Darth Vader he was not ready for it.  Would it not have been a much better plan on the part of Obi-Wan and Yoda to train Luke from a young age and send him in to join the rebellion as a fully trained Jedi knight?

When Anakin was only 9 years old, everyone in the Jedi Council was arguing that he was already too old for Jedi training.  When it comes to Luke, it was a pre-planned agenda to make him a powerful Jedi. So, why did Kenobi wait for Luke to be much older? He could have started Luke's training by himself.


I am currently modifying an existing addons. My workflow is to change something in the python code then restart Blender to see the effect.  Is there a way to update the script without restarting Blender to check result? That would make my development process faster.  Thanks!

I'm currently twiddling with an old addon and insert some print statements for debugging. Currently I'm restarting Blender each time to see the new messages. Is there a way to 'refresh' an already loaded Python script?  An API call would be preferred to disable/re-enable the addon in the User Preferences dialog.


In Java sometimes method parameters act like passed by reference, even though they are not.  what method are they passed by?  I know java is always passed by value. But is it possible that it could act like pass by reference

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Left a lb of ground chuck, still sealed, out on the counter after coming home from buying groceries. It just slipped by me, everything else went into the freezer. It's been about 3 hrs and some change. Still good or should I suck it up and buy another lb? The store is kinda far and huge and a pain in the buns.   I understand that the toxins released by bacteria will still be present after being cooked, but it's still sealed so am I good?  Thanks!  It's one of those round cylindrical packages that are twisted off at the ends. It was not frozen when I bought it, just chilled.

If I left food out of the refrigerator for some period of time, is it still safe? If I left it out too long, can I salvage it by cooking it more?


I am using Ubuntu 14.04 64-bit version Whenever I try to download some software from ubuntu Software Center it used to show “Failed to download package files” error?  So I followed this post   And tried all steps but after following step 5 of this post my software manager is not even allowing me to download rest softwares as well, install button is not coming in front of softwares in software center>  Please help me to get out this problem.  Result in terminal:    shikhar@Shikhar-asus:~$ sudo apt-get update   Get:1 http://dl.google.com stable InRelease 100% [1 InRelease gpgv 3,435 B] [Connecting to archive.ubuntu.com] [Connecting       Splitting up /var/lib/apt/lists/partial/dl.google.com_linux_chrome_deb_dists_stabIgn   http://dl.google.com stable InRelease   E: GPG error: http://dl.google.com stable InRelease: Clearsigned file isn't valid,   got 'NODATA' (does the network require authentication?)

After installing Ubuntu 13.10 I try to install ubuntu-restricted-extras or any software, it shows me:  E: GPG error: http://archive.canonical.com saucy InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication


According to Maxell's Electromagnetic Wave theory, an accelerating charged particle radiates energy and this is one of the arguments due to which the Rutherford model of an atom(In which Rutherford compares electrons revolving around the nucleus to planets revolving around the sun) was rejected.    My question is that even though planets have zero nett charge they are still composed of electrically charged species and if the planet is under constant acceleration due to its revolution, aren't the constituent electrically charged particles of the planet under acceleration? Why don't we see planets emitting photons and spiralling into the sun?

Despite being overall near-netural, I would expect the individual electrons and proton to radiate long EM waves as we accelerate around the Sun or rotate around our poles. Is the acceleration so small that the radiated energy is miniscule?  Or is it that somehow the macroscopic neutrality prevent radiation? If this is so, what mechanism causes single electrons or nuclei to fail to radiate?


I have Microsoft Windows 7 Professional installed on my laptop (HP Pavilion G4 Notebook PC).   Since a couple of weeks my laptop is not shutting down properly. When I click on the shut down button the logging off screen appears then the shutting down screen appears, but after that nothing happens.   I mean the shutting down screen is present all the time and the system does not shut down. The circle next to the shutting down keeps on rotating. I have left it for hours but still nothing happens. Eventually I have to shut it down by pressing the power button for some seconds. But the next time when I start the system, the windows starts normally.    I have tried to find solution for it. Mostly the solution that I found was to check/uncheck the 'Allow computer to turn of this device to save power' in the power management tab of some driver in device manager but nothing seems to work for me.  Could anyone please help me with my problem?

When I installed the last Windows update, all seemed fine except it got stuck doing the restart.  I waited about 5 minutes then used the power button.  Startup was normal.    But then when I told it to shut down it closed the programs then went to the "Shutting Down" screen and just stays there.    Disk activity lights aren't showing any activity.  Here is a screen grab of the most recent updates:    Before I do anything I wanted some input.  Question:  Any ideas of how I can figure out how to fix it?


I've been noticing that many popular login pages separate email and password fields on separate "sections" or pages. Is there a UX benefit or reason for this that I'm not aware of?

My boss has insisted for a while that our login process be divided into two steps on separate pages: on the first page, ask the user's e-mail address. On the second page, either display "user found" and ask for password, or "user not found" and ask for e-mail again.  He insists it is much easier for our users who often forget their credentials or if they even have an account yet. I've long been against this approach because it forces every user to go through two steps every time they login. (I also wonder if it's a security concern, knowing that it will confirm when an email exists in our system.) I would prefer to have a more standard login page with e-mail (all of our usernames are e-mails) and password, and one very clear link for "forgot password?".  Neither of us have any hard data to support our theories, and we have more important things to do than A/B test something that he doesn't think is even a problem. I was just wondering if anyone here could provide some arguments or hard data for or against either approach. I enjoy considering UX design, but I am not an expert.


What is the difference between "Made in..." and "Product of..."? Both are often seen on product labeling; my understanding is that "Made in" is not used for agricultural goods while "Product of" is?

While waiting for the kettle to boil this morning, I was idling and reading the label on the bottle of milk and was struck by the declaration: "Permeate free, made in WA". Here's a shot of the label for proper context:     It's clear that they want to state that the milk is produced in this state, but it sounds odd to me to say that milk is made — I've always associated that with products that require at least a nominal amount of manufacturing/processing (e.g. butter, cream, yoghurt).   For the raw produce though, I can't really recall anything using made but more specific terms like grown, harvested, farmed, raised, etc.  So in this context, does anyone has a suggestion what might be a more descriptive, or more appropriate word? The best I can come up with is milked but that sounds awfully clumsy.   Alternatively, if people have milk bottles from their side of the world that say something similar, then it could just be me that thinks it's a bit clunky.


I read a book maybe 20 years ago about a colony ship that arrived at a new planet and quickly went down to live on the surface. Some kind of acid rain came, killing several colonists. There were some creatures, maybe small Chinese dragon-like things, that could neutralize the rain and protect them. It was part of a series I think. It's not:  The Legacy of Heorot (Jerry Pournelle/Larry Niven/Steven Barnes, 1987) The Faces of Ceti (Mary Caraker, 1991) Founding Father (Isaac Asimov, 1965)

Back when I was young, I recall a interesting sci-fi novel. I recall the book as lacking a title, perhaps due to damage. If I remember right, the book was an antique (cloth cover, stained pages, etc) so odds are it is old. I've been digging for the title of this book but nothing has come back.   Here's a rough outline of the plot:  A bunch of colonists end up on a foreign world after some prospecting. They quickly learn about a problematic aspect of the pine trees that coat the planet. Every couple years, the plants release their seeds. These seeds float down like snow. They are like billions of spiders clinging to strands. Anything they contact is corroded. Due to this, the survivors end up stranded in their shelters until the event passes. Since these seeds look like threads, they are aptly called 'the Thread'. Well, the Thread is the name I remember for them.   I don't believe I ever finished the book. I only remembered it because I was thinking of horror concepts. Any ideas?


I have a string structured in this way:  "Description#Data#IMG"  What's the best method to obtain three distinct strings through the position of sharps?

What is the best way to tokenize/split a NSString in Objective-C?


I left the Schengen in June after staying 88 days. My 90 days outside the Schengen finishes next month. My question is, the 2 days I have left from the last 180 day period - can I add these together with my new 90 days? Can I go I fx. my embassy after two days and have my passport stamped again while in the Schengen?  Hope the question is clear enough and that someone has a word of advice abou this.   Thank you!

I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory:       My situation:  I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation?


First of all I should say that I have very limited computer knowledge so go easy on me. I have Ubuntu 15.10 installed on my laptop and I was trying to to install the driver for the Nvidia video card but an error kept popping up saying that the x  server was on so the installation cannot be completed, so I disabled lightdm and went into the tty terminal and installed the driver (which was a .run file btw) from there, after I was done I started it again but the computer seemed to freeze so I rebooted it now I'm stuck in the login screen and whenever I type my password it just sends me back to the same screen.  I tried going back into the tty and typing  sudo start lightdm  But it said that it failed to connect to socket /com/ubuntu/upstart.  Btw sorry I'm using my phone so I can really format stuff properly.  Update: typing   lspci -k | grep -EA2 'VGA|3D'   Yields this output     Again I apologize for taking a picture of the screen but I can't really do much from my laptop right now.

I just ordered the Nvidia GTX card. I have a dilemma, though. Should I keep using the driver which is available in "additional drivers" in Ubuntu, or should I install the driver from the Nvidia site?  So which driver is the best for me?


I was planning to send an email to someone when actually this person reached me first! I wanted to say "oh I was planning to reach you when you actually reach me first" Like in my native language we have a phrase we use. Is there anything like this in English literature or idiom?

I have the distinct feeling there's a word often used when two people type the same thing at the same time in Internet chat contexts. Not necessarily exactly the same words, but closely related.  Maybe I've even come across it myself but forgotten it. All I can think of now is "Snap!", but that sounds a bit lame in this day and age (who plays cards nowadays, with all these video games?).


I'm trying to achieve something like C's structure, so I predefine a list :  __list = [0] * 1001   everything works well.  but when the list getting complicated (a sample)：  __list = [{"name": '', "score": 0}] * 3  for item in __list:     name, score = input("input name and score split with blank:\n").split()    # raw_input for python2     item['name'] = name     item['score'] = int(score) print(__list)   and I input this:  Lily 23 Paul 12 James 28   out:  [{"name": "James", "score": 28}, {"name": "James", "score": 28}, {"name": "James", "score": 28}]   why?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I'm new to javascript, and really did try to find a solution but I don't know how to apply it to my specific code.  I have two range fields on a form which I want to use as a loan calculator. So, value1 is for the 'loan amount', value2 is for the 'repayment period'. So value1 needs to be divided by value2, and then it needs to output it into an ID called #fullvalue so that I can show the repayment installment value on the form. My code below is working great, however, I can't for the life of me get it right to output the #fullvalue amount to two decimal places. So that it shows like $79.50 instead of something like $75.56789555  $(window).on('load', function() { $("form :input").change(function() { var value1 = $('form #value1').val(); var value2 = $('form #value2').val(); var fullvalue = parseInt(value1, 10) / parseInt(value2, 10); $('form #fullvalue').val(fullvalue); }); });

I would like to format a price in JavaScript. I'd like a function which takes a float as an argument and returns a string formatted like this: "$ 2,500.00"  What's the best way to do this?