Analytic Trigonometry · Superchallenge problem

$x=\dfrac{\pi}{8}+\dfrac{\pi n}{4}$

$x=\dfrac{\pi}{8}+\dfrac{\pi n}{5}$

$x=\dfrac{8}{\pi}+\dfrac{\pi n}{4}$

$x=\dfrac{\pi}{8}-\dfrac{\pi n}{4}$