Question

Solve the following equation for $0^o<\theta <{90}^o$ :

$2\cos 3\theta =1$

Answer 1

$2\cos 3\theta =1$

$\cos 3\theta =\frac{1}{2}$

$\cos 3\theta =\cos {60}^o$

$3\theta ={60}^o$

$\theta ={20}^o$