Trigonometry and Modelling

Medium

For $sin⁡θ≠0\sin \theta \neq 0$ , prove that

$2θ−cot⁡2θ=tan⁡θ\text{cosec } 2\theta - \cot 2\theta = \tan \theta$

[3]

Explain why the identity $2θ−cot⁡2θ=tan⁡θ\text{cosec } 2\theta - \cot 2\theta = \tan \theta$ is not valid when $sin⁡θ=0\sin \theta = 0$ .

[2]

Trigonometry and Modelling Questions