What is the limit as (x,y) approaches (0,0) for the function x^2/(x+y)?

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Homework Statement



Find the limit as (x,y) approaches (0,0):

Homework Equations



x^2/(x+y)

The Attempt at a Solution



I have tried replacing y with 0, mx, x^2, etc. (and likewise with x), and all give me a limit of zero. So I tried to think of ways I could use the definition of a limit, squeeze theorem, L'Hopital's rule, etc. to prove it, but there does not appear to be a way. I'm starting to think that a limit might not even exist. Is there something elementary I'm overlooking?
 
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It is a lot easier to show the limit does not exist. All you have to do is find one path towards (0,0) that produces a limit that is not zero. Maybe you could try a quadratic, or a cubic..
 
I figured it out a while ago. If y=-x, the limit as x->0 is infinity, not zero.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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