SOLUTION: find all the angles between 0� and 180� for which sin2x + 3/4(cos2x) = 0

Question 934787: find all the angles between 0� and 180� for which sin2x + 3/4(cos2x) = 0
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
find all the angles between 0� and 180� for which
sin2x + 3/4(cos2x) = 0
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2sin(x)cos(x) + (3/4)(cos^2(x) - sin^2(x) = 0
8sin*cos + 3cos^2 - 3sin^2 = 0
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3cos^2 + 8sin*cos - 3sin^2 = 0
(cos+3sin)(3cos -sin) = 0
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cos = -3sin or 3cos = sin
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cos/sin = -3 or cos/sin = 1/3
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tan(x) = -3 or tan(x) = 1/3
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x = 108.43 degrees or 288.43 degrees or 18.43 degrees or 198.43 degrees
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Cheers,
Stan H.
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