Answer
$\frac{d(gof)(x)}{dx}=\frac{1}{\frac{df(x)}{dx}}$
Work Step by Step
The given function is:
$(gof)(x)=x$
on differentiating both sides:
$\frac{d(gof)(x)}{dx}\times\frac{df(x)}{dx}=\frac{dx}{dx}$
$\frac{d(gof)(x)}{dx}=\frac{1}{\frac{df(x)}{dx}}$
