is xysin(1/xy) differentiable when xy=0?

Question

I have f defined as it follows:

f=0                     if xy=0

f=xysin(1/xy)     if xy is different from zero.

I found the two partials are 0 if xy=0, but i can't really figure out if it is differentiable in these values

Answer 1

no, sumthun/0....yer quashun blo up