SOLUTION: How many points in the interval 0 ≤ x ≤ 2π satisfy the equation cos 2x = –2 sin x?

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Question 956178: How many points in the interval 0 ≤ x ≤ 2π satisfy the equation cos 2x = –2 sin x?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
How many points in the interval 0 ≤ x ≤ 2π
satisfy the equation cos 2x = –2 sin x?
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cos^2(x)-sin^2(x) = -2sin(x)
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1 - 2sin^2 = -sin
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2sin^2(x) - sin(x) -1
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Factor::
(2sin(x)+1)(sin(x)-1) = 0
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sin(x) = -1/2 or sin(x) = 1
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x = (7/6)pi or x = (11/12)pi or pi/2
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Cheers,
Stan H.
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