Question

Use an angle sum identity to verify the identity cos 2 0 = cos^2 0 -1 .

Answer 1

can you put parentheses? it's difficult to understand whaty ou mean..

Answer 2

$$
cos(2\theta) = cos^2(\theta)-1?
$$

Answer 3

what is "cos 2 0" ?

Answer 4

im not honestly sure i am horriable with algebra its deff my weakest point

Answer 5

cos 2θ = cos^2(θ) − 1/2
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(cos x)^2 - (sin x)^2 = (cos x)^2 - 1/2

(sin x)^2 = 1/2 or sin x = +/- 1 / sqrt(2) = +/- sqrt(2) / 2

x = +/- pi/4. 3.(pi)/4, 5.(pi)/4, 7.(pi)/7
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Answer 6

the real formula is \(\cos(2\theta) = 2\cos^2\theta - 1\).