Define The Function, and partial derivative
Not sure why I'm blanking on this. So far I haven't been having any problems with partial derivatives. And I know the first part is probably easy, and I feel silly for tripping up on it.
Define the function
 =\left\{ {x^{4/3}sin (y/x)\mbox{ if} x\not=0 \atop 0 \mbox{ if} x = 0 )
Compute
)
and )
using the definitions of 
and 
.
As I mentioned, I understand the method of applying the partial derivatives, but I am hung up on the definition portion.
I believe that the approach I would take is the following...
Partially differentiate with respect to x,
\right])
But then I must not be remembering something when finding the derivative when the function is zero... I might get it when I take a break and come back to it, but in the mean time if someone has something that can at least jog my memory, I would appreciate it.
Once I find the partial derivatives, I will have no problem calculating and .
