Question

Find the value of $\theta$ in each of the following :
2 cos 3 $\theta$ = 1

Answer 1

We have,
2 cos 3 $\theta$ = 1
$\Rightarrow 2cos3\theta =\frac{1}{2}\Rightarrow cos3\theta =cos{60}^{\circ }\Rightarrow 3\theta ={60}^{\circ }\Rightarrow \theta ={20}^{\circ }$