3.4.7 Trigonometry (A-level only)

a.

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

\text{cosec } 2\theta - \cot 2\theta = \tan \theta

[3]

b.

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]

a.

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

\text{cosec } 2\theta - \cot 2\theta = \tan \theta

[3]

b.

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]

3.4.7 Trigonometry (A-level only) Questions