Limit Evaluation: (x^4+y^4)/((x^2+y^2)^(3/2)) as (x,y) -> (0,0)

[kasse]

Evaluate the liit of (x^4+y^4)/((x^2+y^2)^(3/2)) when (x,y) approaches (0,0)

I'm trying to replace x and y with rcost and ycost, but it seems too complex. How can I abbreviate the equation?
...

I solved it myself...The limit is 0.

 

[lalbatros]

No need to abbreviate, just analyse the r dependence,
and check that the angular dependence is a has no singularity.

And indeed you are right: 0 is the limit.