Two Variable Limit: Find/Prove Existence

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SUMMARY

The limit of the function Lim [x^2*y^3/(x^4 + y^4] as (x,y) approaches (0,0) can be analyzed by substituting (x,y) = λ(a,b) where a and b are not both zero. Initial attempts to evaluate the limit along specific paths, such as x=y and y=x^2, did not yield consistent results, indicating the need for a more general approach. Graphical analysis suggested that the limit exists, but a formal proof requires demonstrating that the limit is the same regardless of the path taken to the origin.

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Homework Statement


Lim [x^2*y^3/(x^4 + y^4)]
(x,y)->(0,0)
Find the limit or prove it doesn't exist

Homework Equations




The Attempt at a Solution


Tried considering the limit along the line x=y, and y=x^2, but couldn't show there where different vaules of limit for different curves. Then i graphed it, and it looked like the limit exists.
Attempted proof.
|x^2 y^3/(x^4 + y^4) - 0| < E
0< sqrt(x^2 + y^2)< d
this is where I am stuck at.
 
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A simple way is to set e.g. y=0 and then solve it with x->0.

More generally you'd like to move from a general direction to the origin, because sometimes it matters where you're coming from (not in this case).
You can do that by substituting (x,y) = lambda (a,b) where a and b are not both zero.
Then you take the limit for lambda->0.
 

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