The integral is
.
Consider
.
Substitute
.
and
.
Apply derivative on each side with respect to
.
.
Substitute the corresponding values in the integral.
\


.
.
Substitute
and
.
.
(a) Apply integration limits.
\
.
(b)
\Apply trigonometric limits in equation
.
.
If
then
.
If
then
.


.
(a) By the integration limits:
.
(b) By the limits obtained by the trigonometric substitution:
.