1. The problem statement, all variables and given/known data Def. f is Schwarz Differentiable at a pt c in its domain if lim(h->0) [f(c+h)-f(c-h)]/2h exists as a finite limit. 1.)Prove or disprove: f is differentiable at c => f is Schwarz Differentiable at c 2.)Prove or disprove: f is Schwarz Differentiable at c => f is differentiable at c 2. Relevant equations a function f is differentiable at c if lim(x->c) [f(x)-f(c)]/[x-c] exists 3. The attempt at a solution My suspicion, from picturing each derivative, is that 1 is true and 2 is false. To prove 1, I've tried to set h=|x-c| and evaluate the derivative for x>c, and x<c and then use some linear combination of those limits to derive the schwarzian derivative, but I keep running into problems with extra terms.