$\"\"$

\

The integral function is $\"\"$ .

\

Assume $\"\"$ .

\

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

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Substitute $\"\"$ and $\"\"$ in integral function.

\

$\"\"$

\

Trigonometric property : $\"\"$ .

\

$\"\"$

\

$\"\"$

\

Integration reduction fromula : $\"\"$ .

\

$\"\"$

\

$\"\"$

\

Integral fromula : $\"\"$

\

$\"\"$ .

\

$\"\"$

\

Consider $\"\"$ .

\

For a right triangle, $\"\"$ and $\"\"$ .

\

$\"\"$

\

$\"\"$

\

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

\

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

\

Substitute corresponding values in the equation $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

$\"\"$

\

$\"\"$ .