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 :
\
.