The integral is
.
Apply double-angle identity :
.

Evaluate the integral by using substitution method.
\Let
.
Apply derivative on each side with respect to
.

.
Substitute
and
in
.
.
Consider
.
Evaluate the integral by using substitution method.
\Let
.
Apply derivative on each side with respect to
.

Substitute corresponding values in
.

Substitute
in above equation.

Substitute
in above equation.
.
Thus,
.
.