If y=f(x)^φ(x), then (d y)/(d x) is

$e^{\phi \log f}\left\{\frac{\phi}{f} \frac{d f}{d x}+\log f . \frac{d \phi}{d x}\right\}$

$\frac{\phi}{f}\left(\frac{d f}{d x}\right)+\frac{d \phi}{d x} \log f$

$e^{\phi \log f}\left\{\phi \frac{f'}{f}+\phi' \log f'\right\}$

none of these