HELP FAST PLEASE!!!!! Sandra wants to evaluate 2cot(-9pi/2). Herwork is shown below. What did she do wrong? 2cot(-9pi/2)=2cot(9pi/2) 2cot(-9pi/2)=2cot(pi/2) 2cot(-9pi/2)=2(0) 2c…

Question

asked Aug 15, 2019 34.2k views

1 Answer

Mister Nobody · Answer 1 · 2019-08-21T16:09:11+0000

Alright, lets get started.

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

$2 cot((-9\pi)/(2)) = 2 cot((9\pi)/(2))$ Incorrect step

Because as per even/odd identity,

Cot (-Θ) = - cot (Θ)

Hence

$2 cot ((-9\pi)/(2)) = - 2 cot ((9\pi)/(2))$

Now,

It could be written as

$-2 cot ((9\pi)/(2)) = -2 cot ((\pi)/(2))$

-2 * 0

0

Hence the answer is 0. : Answer

Hope it will help :)