This isn't too bad, but I just want to make sure that I have this right.
I'm trying to find the
limit (as h->0) of (yh^3-hy^3)/(h^3+hy^2)
I'm getting -hy. But next I need to calculate the second partial derivative (which was what I was doing in the first place using the limit definition) with respect to y. But obviously I'm getting 0, which I don't think is right.