Analytic Trigonometry · Challenge problem

$\dfrac{\pi}{3}+\pi n,\ \dfrac{2\pi}{4}+\pi n$

$\dfrac{3}{\pi}+\pi n,\ \dfrac{2\pi}{3}+\pi n$

$\dfrac{\pi}{3}-\pi n,\ \dfrac{2\pi}{3}+\pi n$

$\dfrac{\pi}{3}+\pi n,\ \dfrac{2\pi}{3}+\pi n$