Solve the following equations for A, if : 2 cos 2 A = 1

2 cos 2 A = 1 ⇒ cos 2A = ⇒ cos 2A = cos 60° So, 2A = 60° ⇒ A = ⇒ A = 30° Hence, A = 30°.

If 3tan² A - 1 = 0 and angle A is acute, the measure of angle A is :
20°
45°
60°
30°