Question

HELP FAST PLEASE!!!!!

Answer 1

Alright, lets get started.

The answer Sandra got is correct that is zero but there are some mistakes she made while writing steps.

$2 cot(\frac{-9\pi}{2}) = 2 cot(\frac{9\pi}{2})$ Incorrect step

Because as per even/odd identity,

Cot (-Θ) = - cot (Θ)

Hence

$2 cot (\frac{-9\pi}{2}) = - 2 cot (\frac{9\pi}{2})$

Now,

It could be written as

$-2 cot (\frac{9\pi}{2}) = -2 cot (\frac{\pi}{2})$

$-2 * 0$

0

Hence the answer is 0. : Answer

Hope it will help :)