Let be differentiable on an open interval containing with and

MATHEMATICS · Single correct · AP · Calculus AB · Differentiation: Composite, Implicit, and Inverse Functions · Differentiation: Composite, Implicit, and Inverse Functions

Problem

Let ff be differentiable on an open interval containing x=2x=2 with f(2)=5f(2)=5 and f′(2)=0f'(2)=0. Which statement best explains why the inverse function of ff is not differentiable at x=5x=5? (a) Because f′(2)=0f'(2)=0, the inverse has derivative 00 at x=5x=5. (b) Differentiability of ff at x=2x=2 guarantees differentiability of f−1f^{-1} at x=5x=5 regardless of the value of f′(2)f'(2). (c) Because f′(2)=0f'(2)=0, the reciprocal needed to compute (f−1)′(5)(f^{-1})'(5) is undefined, so the inverse is not differentiable there. (d) Since f′(2)=0f'(2)=0, (f−1)′(5)=10=0(f^{-1})'(5)=\dfrac{1}{0}=0, so the inverse is differentiable at x=5x=5.

Related theory

Browse the problem library