Mathematics

Mathematics

Problem

Which of the following identities is always true for any acute angle θ\theta? a) sin⁡θ+cos⁡θ=1\sin\theta + \cos\theta = 1 b) sin⁡2θ+cos⁡2θ=1\sin^{2}\theta + \cos^{2}\theta = 1 c) tan⁡2θ+1=cot⁡2θ\tan^{2}\theta + 1 = \cot^{2}\theta d) sec⁡θ−tan⁡θ=1\sec\theta - \tan\theta = 1

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