$\"\"$

\

Show that $\"\"$ .

\

Rewrite the above requation.

\

$\"\"$

\

consider $\"\"$ then $\"\"$ .

\

The function is $\"\"$ .

\

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

\

$\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

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

\

$\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

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

\

$\"\"$ .

\

$\"\"$

\

$\"\"$ .