Question

Prove that: sin8A/1-cos8A=cot4A​

Answer 1

Step-by-step explanation:

Recall the identity

$\tan \frac{A}{2}= \dfrac{1 - \cos A}{\sin A}$

We can see that

$\dfrac{\sin 8A}{1 - \cos 8A} = \dfrac{1}{\tan 4A}= \cot 4A$