SOLUTION: How do you solve: sin^2(x)+cos(2x)-cos(x)=0 I know that cos(2x) can be equal to cos^2(x)-sin^2(x), or it can be equal to 2cos^2(x)-1, or it can be equal to 1-2sin^2(x) My

Question 454350: How do you solve:
sin^2(x)+cos(2x)-cos(x)=0
I know that cos(2x) can be equal to cos^2(x)-sin^2(x), or it can be equal to 2cos^2(x)-1, or it can be equal to 1-2sin^2(x)
My math teacher told us to use the formula that has the trig-word in it that is in the equation, but since both sin and cos are in the equation, I'm not sure what to use.
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
if you use cos^2(x)-sin^2(x) then you will have sin^2(x)+cos^2(x)-sin^2(x)
which eliminates sin completely.
leaving you cos^(2x)-cos(x)

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