SOLUTION: Find, to the nearest tenth of a degree, all values of x in the interval 0degree <_ x < 360degree that satisfy the equation 8 cos^2 x - 2 cos x - 1 = 0
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Question 752989: Find, to the nearest tenth of a degree, all values of x in the interval 0degree <_ x < 360degree that satisfy the equation 8 cos^2 x - 2 cos x - 1 = 0 Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Find, to the nearest tenth of a degree, all values of x in the interval 0degree <_ x < 360degree that satisfy the equation
8 cos^2 x - 2 cos x - 1 = 0
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Factor:
8cos^2 -4cos + 2cos -1 = 0
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4cos(2cos-1) + (2cos-1) = 0
(2cos-1)(4cos+1) = 0
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cos(x) = 1/2 or cos(x) = -1/4
x = +-60 degrees or x = 104.48 or x = 255.52
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Cheers,
Stan H.
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