Exams › SSC CGL (Prelims) › General

If \(\cos(90^\circ-\theta)=\sin(2\theta)\), what is \(\theta\)?

1. 60°
2. 30°
3. 45°
4. 90°

Correct answer: 60°

Solution

Using the identity \(\cos(90^\circ-\theta)=\sin\theta\), the equation becomes \(\sin\theta=\sin(2\theta)\). For the given options, \(\theta=60^\circ\) satisfies \(\sin 60^\circ=\sin 120^\circ\).

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