JAMB 1993 · UME · Q39

If $\sin\theta = \cos\theta$ , find $\theta$ between $0^\circ$ and $360^\circ$ .

Worked solution (try it first)

Divide both sides by $\cos\theta$ : $\tan\theta = 1$ .
The acute angle with $\tan\theta = 1$ is $45^\circ$ .
Tangent is positive in the first and third quadrants, so $\theta = 45^\circ$ or $180^\circ + 45^\circ = 225^\circ$ , option A.