Question

if 2 cos 3A= 1 find A​

Answer 1

Step-by-step explanation:

cos3A=1/2

3A=cos-1 1/2

3A=π/3

A=π/9

Answer 2

Answer:

A = 20°

Step-by-step explanation:

$2 \cos(3a) = 1 \\ \\ \cos(3a) = \frac{1}{2}$

We know,

$\cos(60) = \frac{1}{2}$

Therefore

$3a = 60 \\ \\ a = 20$