SOLUTION: Solve 2 sin^2 x + cos x -2=0 on the interval -pi< x < pi

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Question 733332: Solve 2 sin^2 x + cos x -2=0 on the interval -pi< x < pi
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Solve 2 sin^2 x + cos x -2=0 on the interval 0 < x < 2π
2 sin^2 x + cos x -2=0
2(1-cos^2x)+cosx-2=0
2-2cos^2x+cosx-2=0
-2cos^2x+cosx=0
cosx(1-2cosx)=0
cosx=0
x=π/2, 3π/2
or
1-2cosx=0
2cosx=1
cosx=1/2
x=π/6, 11π/6 (in Q1 and Q4 where cos>0)