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kondaur [170]
2 years ago
10

If cos2A=11/25, show that cosA=6/5√2​

Mathematics
1 answer:
Hatshy [7]2 years ago
7 0

Answer:

it is not I think...

Step-by-step explanation:

Using the identity

\cos(2a) = 2 \cos^2(a) - 1

We can solve:

2 \cos^2(a) - 1 = \frac{11}{25}

2 \cos^2(a) = \frac{36}{25}

\cos^2(a) = \frac{18}{25}

\cos(a) = \sqrt \frac{18}{25}

\cos(a) = \sqrt{ 2 \cdot \frac{3^2}{5^2} }= \frac35 \sqrt 2

So whoever asked the question forgot the factor 2!!!

Or did I miss anything??

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Given the polynomial 21x 4 + 3y - 6x 2 + 34 What polynomial must be subtracted from it to obtain 29x 2 - 7 ? What polynomial mus
fredd [130]

Answer:

1. 21x⁴+3y-35x² + 41

2. -21x⁴-3y+6x² + x

Step-by-step explanation:

When adding and subtracting polynomials , you can use the distributive property to add or subtract the coefficients of like terms.

1. The polynomial is 21x⁴ + 3y -6x² + 34

To obtain polynomial 29x² -7 , we must subtract some polynomial from it.

Let that polynomial be k.

So, 21x⁴ + 3y -6x² + 34 - k =  29x² -7

k = 21x⁴ + 3y - 6x² +34 - 29x² +7 = 21x⁴ + 3y - 35x² + 41

2. To obtain a first degree polynomial, let that polynomial be x +34

So, 21x⁴ + 3y - 6x² + 34 + K = x + 34

K = x + 34 - 21x⁴ -3y + 6x² - 34

  = -21x⁴ - 3y + 6x² + x

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Which of the following is x=-5 a solution ?
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Answer:

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Step-by-step explanation:

Plug X in and see which equations/expressions are true

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Jessica has a shelf that is 26 inches long . If she cuts off 12 3/8 inches what is the new length of the shelf ?
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Step-by-step explanation:

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hope this answer helps you dear take care and may u have a great day ahead!

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