If g is the inverse of function f and f'(x) = sin x, then g'(x) =
Answer & explanation
Correct answer: option 3
Since g is the inverse of function f. Therefore,
fog(x) = x for all x
$\Rightarrow \frac{d}{d x}(fog(x))=\frac{d}{d x}(x)$ for all x
$\Rightarrow \frac{d}{d g(x)}\{f(g(x))\} . g'(x)=1$ for all x
$\Rightarrow \sin \{g(x)\} g'(x)=1$ for all x
$\Rightarrow g'(x)=\frac{1}{\sin \{g(x)\}}$ for all x