# Two Path Test

by mharten1
Tags: path, test
 P: 63 1. The problem statement, all variables and given/known data Use the two path test to prove that the following limits do not exist. 2. Relevant equations $$\lim_{(x,y)\rightarrow{(0,0)}}\frac{4xy}{3x^2+y^2}$$ 3. The attempt at a solution The book that I am using introduces the Two Path Test theoretically but does not show an example of how to do it, so I am a bit lost. Would I set x = y, and x = -y? In some of the more basic problems I was able to set x = 0 and y = 0, and find the limits would differ, proving that there was no limit. But in this case, that's obviously not possible.
 Sci Advisor HW Helper Thanks P: 25,228 Those two paths look like a good choice to me. Try them out. What's the limit along each path?
P: 63
 Quote by Dick Those two paths look like a good choice to me. Try them out. What's the limit along each path?
I'm getting 1 and -1, thus the limit does not exist. A question that I have that the book does not address: how do I choose the paths? Do you just try what you think will work until you find something, or is there a specific method of choosing?