Answer the following questions about fundamental trigonometric identities.

MATHEMATICS · Multi-part · CBSE · Mathematics · Introduction to Trigonometry · Introduction to Trigonometry

Problem

Answer the following questions about fundamental trigonometric identities. (i) Starting with sin⁡2θ+cos⁡2θ=1\sin^{2}\theta+\cos^{2}\theta=1, derive the relation sec⁡2θ−tan⁡2θ=1\sec^{2}\theta-\tan^{2}\theta=1. (ii) Using a similar method, derive csc⁡2θ−cot⁡2θ=1\csc^{2}\theta-\cot^{2}\theta=1 from the primary identity. (iii) Explain, in words and symbols, why the expressions sec⁡2θ−tan⁡2θ\sec^{2}\theta-\tan^{2}\theta and csc⁡2θ−cot⁡2θ\csc^{2}\theta-\cot^{2}\theta are each equal to a constant for every permissible value of θ\theta.

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