Let f be a real value function and x Î Df

Question

then
0
lim ( ) ( )
h
f x h f x
® h
+ -
when it exists is
called
A) The derivative of f at a
B) The derivative of f at h
C) The derivative of f at x
D) The derivative of f at x = h

Answer 1

Can't read your funky fonts, but since
there are no a's involved, and
there x's and h's,

I'd say (C)