The function is
,
.
Apply first derivative with respect to
.


Find the relative extrema , by equating
.




or
Solve for 
The general solution of sine function
is
.
Where 
Then the values of
are
,
,
.....
Solve for 


The general solution of sine function
is
.
Where 
The values of
are
,
,
....
So the critical values of
are
,
,
and
.
Substitute
in
.

Substitute
in
.

Substitute
in
.

Substitute
in
.

The relative extrema points are
,
,
and
.
Using the second derivative test.
\Apply second derivative with respect to
.




| Point | \![]() | \
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Sign of ![]() | \
\
| \
\
| \
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| \
Conclusion \ | \
\
Relative maximum \ | \
Relative maximum | \ \
Relative minimum \ | \
\
Relative minimum \ | \
The relative maximum at
and
.
The relative minimum at
and
.