Answer
(a) $2$
(b) $\frac{1}{2}$
Work Step by Step
By Theorem 5.9, we have:
$(f^{-1})'(x) = \frac{1}{f'(f^{-1}(x))}$
Therefore, $(f^{-1})'(-1/2) = \frac{1}{f'(f^{-1}(-1/2))} =\frac{1}{f'(-1)} = \frac{1}{1/2} =2$
And, $(f^{-1})'(1) = \frac{1}{f'(f^{-1}(1))}= \frac{1}{f'(2)} = \frac{1}{2}$