If for an acute angle

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

If sin⁡θ+cos⁡θ=2 sin⁡θ\sin\theta + \cos\theta = \sqrt{2}\,\sin\theta for an acute angle θ\theta, what is θ\theta? (a) 60∘60^{\circ} (b) 67.5∘67.5^{\circ} (c) 22.5∘22.5^{\circ} (d) 45∘45^{\circ}

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