SOLUTION: Solve 2cos^2 x + cos x -1= 0 algebraically over the set of real numbers. Give the general solution using exact values. Thanks

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Question 821184: Solve 2cos^2 x + cos x -1= 0 algebraically over the set of real numbers. Give the general solution using exact values.
Thanks

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Solve 2cos^2 x + cos x -1= 0 algebraically over the set of real numbers. Give the general solution using exact values.
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For interval[0,2π]
2cos^2 x + cos x -1= 0
(2cosx-1)(cosx+1)=0
..
2cosx-1=0
cosx=1/2
x=π/3,5π/3
or
cosx+1=0
cosx=-1
x=π