# Math Help - Is there such a function?

1. ## Is there such a function?

is there a function f: A (subset of R^n) -> r such that (f)yx exists on R^2 but (f)x exists nowhere?

2. What is r? What are (f)yx and (f)x? Please use latex to make your question readable..

3. Sorry. I should really learn to use LaTex. It's R -the set of real numbers. that was a typo.

And fx - partial derivatve wrt x.

(f)yx - mixed artial derivaive of f.