The trigonometric equation is
.
Apply sine half-angle identity :
.

Apply zero product property.
\
Solve
.

The general solution of
is
, where
is an integer.
The solution is
, where
is an integer.
Now find the solutions on the interval
.
If
,
.
If
,
.
Thus, the solutions are
and
on the interval
.
Solve
.

The general solution of
is
, where
is an integer.
The solution is
, where
is an integer.
Now find the solutions on the interval
.
If
,
.
If
,
.
Thus, the solutions are
and
on the interval
.
The solutions of
are
,
,
and
on the interval
.