Question

If $\cos \theta =1$, then find the value of acute angle $\theta$.

Answer 1

Given, $\cos \theta =1$ ...(i)
But $\cos 0^{\circ }=1$ ...(ii)

From equations (i) and (ii):
$\cos \theta =\cos 0^{\circ }$
$\therefore \theta =0^{\circ }$