Question 448352: can you please help me solve this trigonometric equation:
2sin^2x-cosx-1=0
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! can you please help me solve this trigonometric equation:
2sin^2x-cosx-1=0
..
for 0
2sin^2x-cosx-1=0
2(1-cos^2x)-cosx-1=0
2-2cos^2x-cosx-1=0
-2cos^2x-cosx+1=0
2cos^2x+cosx-1=0
(2cosx-1)(cosx+1)=0
2cosx-1=0
cosx=1/2
x=π/3,5π/3
..
cosx+1=0
cosx=-1
x=π
..
ans:
x=π, π/3, 5π/3
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