(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Let :

[tex]f(x,y) = \frac{xy(x^2 - y^2)}{(x^2 + y^2)^2}[/tex] if [tex](x,y) \neq (0,0)[/tex]

[tex]f(x,y) = 0[/tex] if [tex](x,y) = (0,0)[/tex]

a) Find [tex]f_{xx}(0,0)[/tex]

b) Find [tex]f_{xy}(0,0)[/tex]

c) Find [tex]f_{yx}(0,0)[/tex]

2. Relevant equations

None

3. The attempt at a solution

I'm not sure how to deal with the piecewise defined function, I just took the first and second partial derivatives w/ respect to x (for part a), but then still I can't evaluate the resulting function at (0,0), because at the point it doesn't exist...

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Partial Derivative, piecewise function

**Physics Forums | Science Articles, Homework Help, Discussion**