You can put this solution on YOUR website! find the all values of x in the interval [0,2pi] such that sin(2x)=cos(x)
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sin(2x) = cos(x)
2sin(x)cos(x) = cos(x)
2sin(x)cos(x) - cos(x) = 0
cos(x)*(2sin(x) - 1) = 0
cos(x) = 0
sin(x) = 1/2
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Can you do the rest?