Let f(x) = I f(x th) - f(x) Then the expression can be written in the form h A I(r th) where A is a constant and A : Using your answer from above we have: f'(x) = lim f(x th) - f(x) h +0 h Finally, find each of the following: f' (1) = f' ( 2 ) = f' (3) =