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DIA [1.3K]
3 years ago
11

Find an exact value. cosine of negative seven pi divided by twelve

Mathematics
2 answers:
NemiM [27]3 years ago
5 0
We want to find cos(-7π/12).

Let x = -(7π)/12.
Then 2x = -(7π)/6.

Note that
cos(2x) = 2cos²x - 1, or
cos x = +/- √([1 + cos(2x)]/2)

Because -(7π)/6 is in the 3rd quadrant, with a reference angle of π/6.
cos(-7π/6) = -cos(π/6) = -√3/2 = -0.866.
Also, -(7π)/12 is in the 2nd quadrant, therefore it's cosine is negative.

Therefore, obtain
cos(-7π/12) = -√[0.5*(1 - 0.866)] = -0.2588.

Answer: -0.2588
hodyreva [135]3 years ago
5 0

Answer:

(the square root of 2 minus the square root of 6) / 4

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Simplify each exponential expression using the properties of exponents and match it to the correct answer.
Dimas [21]

Answer:

(3^(3))(4^(0))^(2)(3*2)^(-3)(2^(2))=1/2

((2*3)^(-1)*2^(0))/((2*3)^(-1))=1

((3^(7)*4^(7))(2*5)^(-8)(5^(2)))/(12^(7)*5^(-1)*2^(-4))= 1/50000

Step-by-step explanation:

6 0
2 years ago
What’s the measure of angle c?<br><br><br> Some please answer fast. Please.
kow [346]

Answer: 42

Step-by-step explanation:

Ok what you want to do is add all of them up and equal it to 180 because a triangle is 180 degrees .

Your equation should look like this

9x-3+22x+1+42-3x = 180

What you want to do first is combine all the x and numbers on the left side so it should look like this

1) 28x+40= 180

Then you want to subtract 40 on both sides so it will look like this

2)28x=140

You want to get x by it self so you divide 28 on both sides

3) x=140/28

4) x=5

Since you are finding c you have to insert 5 into x

1) 9(5)-3

2)45-3

Then your answer should be 42

6 0
3 years ago
Ms.Friedman and Mrs.Elliot both teach sixth grade math. They share a storage closet. What is the total area of both rooms and th
Citrus2011 [14]
Answer:
Total area of both rooms and the storage = 2844 ft^2

Explanation:
Total area would initially be the summation of the area of Ms. Friedman's room and storage added to Mrs. Elliot's room and storage.
However, we are given that the storage is shared.
So now, the total area would be equal to Ms. Friedman's room and storage + Mrs. Elliot's room and storage - area of closet

Now, we can notice that:
Ms. Friedman's room and storage = Mrs. Elliot's room and storage

Therefore:
Total area = 2*Ms. Friedman's room and storage - area of storage

1- getting area of Ms. Friedman's room and storage:
length = 36 ft 
width = 40 ft
area of Ms. Friedman's room and storage = length * width
area of Ms. Friedman's room and storage = 36 * 40
area of Ms. Friedman's room and storage = 1440 ft^2

2- getting area of closet:
length = 36 - 30 = 6 ft
width = 40 - 34 = 6 ft
area of closet = length * width
area of closet = 6 * 6 = 36 ft^2

3- total area of both rooms and the storage:
Total area = 2*Ms. Friedman's room and storage - area of storage
Total area = 2*1440 - 36 
Total area = 2844 ft^2

Hope this helps :)

8 0
3 years ago
Please help!!!! and when you answer please explain how you got it so in the future I can understand it
UNO [17]

Answer:

It does

Step-by-step explanation:

This is because the line has points in which time and distance are connected (Ex. 100 and 2)

Hope this helps! :)

7 0
3 years ago
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