.
First thing you need to know and to apply is
= cot(x) =
.
When you apply it, your equation becomes
=
, or
=
.
Second thing you need to know is 2*cos(x)*sin(x) = sin(2x).
When you apply it, the last equation becomes
sin(2x) =
.
It has the solutions 2x =
, 2x =
, 2x =
and 2x =
.
Therefore, the solutions for x are
,
,
and
.
Solved.