The integral is
.
The indicated trignometric subustitution is
.
Subustiute
and
.
.
.
.
Trigonometric identity :
.
.



Consider
.
Apply derivative on each side with respect to
.
.

Subustiute
and
in the integral.
.
Sum and difference rule of integration :
.
.

Substitute
in the above integral.
.
The indicated trignometric subustitution is
.

In the right triangle
and
.

Find
Therefore, substitute
in equation
.

.
Associate Right Triangle :
\
.