Trigonometric Equations · Superchallenge problem

$x=\tfrac{\pi}{6},\ \tfrac{\pi}{3}$

$x=\tfrac{\pi}{12},\ \tfrac{\pi}{2}$

$x=\tfrac{\pi}{6},\ \tfrac{\pi}{2}$

$x=\tfrac{6}{\pi},\ \tfrac{\pi}{2}$