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3 years ago

How do you find the general solution for cos2A=cos^2A

Mathematics

1 answer:

eduard3 years ago

6 0

Answer:

A = 0 +/- nπ radians , where n is an integer.

Step-by-step explanation:

cos 2A = cos^2 A

Use the identity cos 2A = 2 cos^2 A -1 :

2cos^2 A - 1 = cos^2 A

cos^2 A = 1

Cos A = +/-1

When cos A = 1, A = 0 +/- 2nπ radians.

when cos A = -1, A = π +/- nπ radians.

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X-y+z=-4 3x+2y-z=5 -2x+3y-z=15 How do I solve this?

Lera25 [3.4K]

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$z=-4-x+y\\.\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ and\\ \left \{ {{4x+y=1\ \ \ \ } \atop {-x+2y=11\ /\cdot4}} \right. \\\\\left \{ {{4x+y=1\ \ \ \ } \atop {-4x+8y=44}} \right. \\-------\\y+8y=1+44\\9y=45\ /:9\\y=5\\\\-x+2y=11\ \ \ \Rightarrow\ \ \ x=2y-11\ \ \ \Rightarrow\ \ \ x=2\cdot5-11=-1\\\\z=-4-x+y=-4-(-1)+5=-4+1+5=2\\\\Ans.\ x=-1\ \ \ and\ \ \ y=5\ \ \ and\ \ \ z=2$

5 0

3 years ago

Manny makes the following purchases at the store:

Anna [14]

The correct answer is:

He paid the correct amount.

Explanation:

First we find the subtotal of Manny's items:

32.65+3(14.89)+39.99 = 32.65+44.67+39.99 = 117.31

Next, we calculate the discount. If he gets 10% off, this means he pays 100%-10% = 90% of the total. 90% = 90/100 = 0.9:

0.9(117.31) = 105.579

Next we calculate the tax. Since tax is 8%, this means he pays 100% of his subtotal after discount plus the 8% tax; 100%+8% = 108%; 108% = 108/100 = 1.08:

1.08(105.579) = 114.02532 ≈ 114.03

Since this is what he paid, he paid the correct amount.

8 0

3 years ago

Read 2 more answers

Ari restaurant, all the freezers are set to a temperature that is below 3°F.

prohojiy [21]

Answer:

Answer is A

Step-by-step explanation:

X is below -3

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2 years ago

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Vinil7 [7]

The answer is 83
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