You can put this solution on YOUR website! solve cos square x - 2sinxcosx - sin square x = 0, 0< or equal to 2x < or equal to pi?
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cos^2(x)-2sin(x)cos(x) -sin^2(x) = 0
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Factor: to get:
(cos(x)-sin(x))^2 = 0
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cos(x) = sin(x) where 0<= 2x <= pi
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cos(x) = sin(x) where 0<= x <= pi/2
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x = pi/4
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Cheers,
Stan H.