The function is
.
Derivative on each side with respect to
.

Derivative of inverse trigonometric functions:
.

To find the relative extrema, solve
.

Squares on each side.
\
Let
.

The above equation is in the form of a quadratic equation 
The roots of the quadratic equation is
.
Compare
with
.


Substitute
in above value.
.


The negative root is not considered since,
can not be negative.
Critical point is 

Substitute
in
.

The point is
.
Substitute
in
.

The point is
.
.
Derivative on each side with respect to
.

Identify the nature of the extrema points.
\| Point | \Sign of ![]() | \
Conclusion | \
![]() | \
\
| \
Relative maximum | \
![]() | \
\
| \
Relative minimum | \
The relative maximum point is
.
The relative minimum point is
.