SOLUTION: Find all solutions to the equation. cos2x + 2 cos x + 1 = 0

Question 906637: Find all solutions to the equation.
cos2x + 2 cos x + 1 = 0
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Find all solutions to the equation.
cos2x + 2 cos x + 1 = 0
(2cos^2-1) + 2cos + 1 = 0
2cos^2 + 2cos = 0
(cos)(2cos+2) = 0
cos(x) = 0 or cos(x) = -1
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x = pi/2 or (3/2)pi or x = pi
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Cheers,
Stan H.
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