Fast ! 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) 2cot(-9pi/2)=0

Alright, lets get started.

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

Incorrect step

Because as per even/odd identity,

Cot (-Θ) = - cot (Θ)

Hence

Now,

It could be written as

0

Hence the answer is 0. : Answer

Hope it will help :)

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total amount of money that he should pay if he has not used his duty free exemption is $98

step-by-step explanation:

given a united states citizen returning to the states declares the following items at the customs office: 3 shirts at $8.50 each 2 dresses at $27.50 each 1 pair of gold cuff links at $17.50 per pair. we have to find how much he pay

cost of 3 shirts if one cost at $8.50 is

cost of 2 dresses if one cost at $27.50 is  

cost of 1 pair of gold cuff at $17.50

so, total amount of money that he should pay if he has not used his duty free exemption is   $25.5+$55+$17.50=$98