<p>An indifference curve can touch the axes, take for example the case of perfect substitutes, if the consumer his utility is given by
 U=x1+x2
 then obviously he is indifferent between bundle (10,0) and (0,10). So not touching the axes is not a characteristic of indifference curves as such, even though in the case of Cobb-Douglas functions it holds.</p>

<p>As for your other concern, whether an indifference curve can take as input only one good, with the other input being money: this is perfectly possible, it is even a more general case than the indifference curve for two goods. In the case of the inputs x1= a good and m=money held by the consumer we can formalize the utility maximization problem in the following way: 
max U=u(x1,m)
Subject to the constraint: b=p1x1+m
As you see the standard form can be used with just one change: the price of a unit money held is of course 1.</p>

<p>And now the more general case, again let x1 be a good the consumtion of which we are interested in and now let y be the MONEY SPENT on all other goods. Now again we can use the modification of the budget constraint above. That is: price of y is 1. 
In short: anything can be an input in an utility function, just think about your own preferences: you dont just enjoy goods, you enjoy holding money and giving to charity etc. but also spending time with friends/family, with some modifications all this can be put in the form of a utility maximization problem and thus an indifference curve can be constructed for any two inputs, holding other inputs fixed.</p>

CC BY-SA 4.0
2019-01-08T12:20:51.553Z
2019-01-08T12:20:51.553Z
user18214
<p>As already mentioned by others indifference curves can touch the axes.</p>

<p>I think that here some confusion arises from the language that people usually use. When we say being indifferent between two goods we mean between holding or consuming two goods. And indifference curve gives you all bundles that satisfy this.</p>

<p>In the same manner you can be indifferent between goods and services, goods and leisure or as in your example goods and money.</p>

<p>To construct indifference curve you need just two alternatives. Here you don’t have indifference curve for one good with itself but an indifference curve for two alternatives, one holding money which you may like to do and second alternative is purchasing given good.</p>

CC BY-SA 4.0
2019-01-08T12:34:11.847Z
2019-01-08T12:34:11.847Z
1muflon1
<p>The characteristic feature of indifference curve is that it will not touch the X axis or Y axis. But as a special case it will touch the Y axis if the combination is between Money and Commodity. "If money is taken on Y-axis, then IC curve can touch oy-axis" here we have taken 'money' on Y-axis and 'commodity' on X-axis. Here my doubt is could we use indifference curve for one commodity? If so please explain me with an example.<img src="https://i.sstatic.net/5S0vE.jpg" alt="enter image description here"></p>

CC BY-SA 4.0
2019-01-08T12:20:51.163Z
Indifference curves can touch the axis. In that case, preferences are not strictly convex.
Patricio
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2019-01-08T14:27:55.087Z
@Patricio Please post answers as answers so I can downvote them when they are incorrect. (I also like to upvote when they are correct.)
Giskard
CC BY-SA 4.0
2019-01-08T17:49:16.330Z
@denesp, I thought mine wasn't aproper answer, just a comment
Patricio
CC BY-SA 4.0
2019-01-14T15:43:06.653Z
@Patricio: Your comment is incorrect in that convex preferences can generate indifference curves that intersect the axes. An example is the quasi-linear preference $u(x,y)=\sqrt x+y$.
Herr K.
CC BY-SA 4.0
2019-01-16T09:08:59.120Z
@HerrK.I was under the impression that strict convexity guarantees an interior solution (one with $x>0,y>0$). That is not the case with quasi-linear preferences (in your example, income needs to exceed $\frac{p_y^2}{4p_x}$ in order for the consumer to be willing to consume some amount of good $y$)
Patricio
CC BY-SA 4.0
2019-01-16T13:23:47.123Z
@HerrK.A friend has pointed out that my previous comment can be construed as disrespectful and I didn't intend that. I'm sorry if it bothered you.
Patricio
<microeconomics><consumer-theory>
feature of indifference curve
Nandy
# feature of indifference curve

(Asked by: username_0 on 2019-01-08)

The characteristic feature of indifference curve is that it will not touch the X axis or Y axis. But as a special case it will touch the Y axis if the combination is between Money and Commodity. "If money is taken on Y-axis, then IC curve can touch oy-axis" here we have taken 'money' on Y-axis and 'commodity' on X-axis. Here my doubt is could we use indifference curve for one commodity? If so please explain me with an example.![enter image description here](https://i.sstatic.net/5S0vE.jpg)

**Tags:** microeconomics, consumer-theory

> **Comments:**
> **username_1**: Indifference curves can touch the axis. In that case, preferences are not strictly convex.  
> **username_2**: @username_1 Please post answers as answers so I can downvote them when they are incorrect. (I also like to upvote when they are correct.)  
> **username_1**: @denesp, I thought mine wasn't aproper answer, just a comment  
> **username_3**: @username_1: Your comment is incorrect in that convex preferences can generate indifference curves that intersect the axes. An example is the quasi-linear preference $u(x,y)=\sqrt x+y$.  
> **username_1**: @username_3I was under the impression that strict convexity guarantees an interior solution (one with $x>0,y>0$). That is not the case with quasi-linear preferences (in your example, income needs to exceed $\frac{p_y^2}{4p_x}$ in order for the consumer to be willing to consume some amount of good $y$)  
> **username_1**: @username_3A friend has pointed out that my previous comment can be construed as disrespectful and I didn't intend that. I'm sorry if it bothered you.  

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## 2 answers

### Answer by username_4 on 2019-01-08. Score: 2

An indifference curve can touch the axes, take for example the case of perfect substitutes, if the consumer his utility is given by
U=x1+x2
then obviously he is indifferent between bundle (10,0) and (0,10). So not touching the axes is not a characteristic of indifference curves as such, even though in the case of Cobb-Douglas functions it holds.

As for your other concern, whether an indifference curve can take as input only one good, with the other input being money: this is perfectly possible, it is even a more general case than the indifference curve for two goods. In the case of the inputs x1= a good and m=money held by the consumer we can formalize the utility maximization problem in the following way:
max U=u(x1,m)
Subject to the constraint: b=p1x1+m
As you see the standard form can be used with just one change: the price of a unit money held is of course 1.

And now the more general case, again let x1 be a good the consumtion of which we are interested in and now let y be the MONEY SPENT on all other goods. Now again we can use the modification of the budget constraint above. That is: price of y is 1.
In short: anything can be an input in an utility function, just think about your own preferences: you dont just enjoy goods, you enjoy holding money and giving to charity etc. but also spending time with friends/family, with some modifications all this can be put in the form of a utility maximization problem and thus an indifference curve can be constructed for any two inputs, holding other inputs fixed.


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### Answer by username_5 on 2019-01-08. Score: 0

As already mentioned by others indifference curves can touch the axes.

I think that here some confusion arises from the language that people usually use. When we say being indifferent between two goods we mean between holding or consuming two goods. And indifference curve gives you all bundles that satisfy this.

In the same manner you can be indifferent between goods and services, goods and leisure or as in your example goods and money.

To construct indifference curve you need just two alternatives. Here you don’t have indifference curve for one good with itself but an indifference curve for two alternatives, one holding money which you may like to do and second alternative is purchasing given good.


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