I have a problem with the next exercise:
Given de function with
a) Find y for t=0
The thing is that I've found that f isn't differentiable at (0,0). The partial derivatives exists at that point, I've found them by definition.
And then I saw if it was differentiable at that point.
In the polar form it gives that this limit doesn't exists, so it isn't differentiable at that point. So I can't apply the chain rule there, right?
To ensure the differentiability of a composed function, both function must be differentiable. If one isn't, then the composition isn't differentiable at a certain point. Right?
Bye there, and thanks.