$\"\"$

The function is $\"\"$ .

Take logarithm of each side.

$\"\"$

Power property of logarithms : $\"\"$ .

$\"\"$

Apply derivative on each side with respect to $\"\"$ .

$\"\"$

Product property of derivatives : $\"\"$ .

$\"\"$

Substitute $\"\"$ in the above equation.

$\"\"$

$\"\"$

$\"\"$