The chosen topic is not meant for use with this type of problem. Try the examples below.
[tex]cot (3x),x=\frac{2\pi }{3}[/tex]
[tex]cot ( \frac{x}{2}, x=\frac{\pi }{2}[/tex]
[tex]cos (x), x = \frac{x}{2}[/tex]
