The trigonometric equation is
.
Rewrite the equation as
.
.
To solve
on a calculator, first set the mode to radians.
If
.

.
One solution of the equation
is
.
The general solution of
is
, where
is an integer.
Thus,
.
Substitute
in the above expression.
.
is not in the interval
.
is another solution of the equation
.
The solution set for
is
.
The solution set for
is
.