SOLUTION: find the exact value of cos 2 theta given cosine of theta = negative 12 over 13 and theta is between 180 degrees and 270 degrees.

Question 832782: find the exact value of cos 2 theta given cosine of theta = negative 12 over 13 and theta is between 180 degrees and 270 degrees.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
find the exact value of cos 2 theta given cosine of theta = negative 12 over 13 and theta is between 180 degrees and 270 degrees.
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cos(2t) = cos^(t)-sin^2(t) = 2cos^2(t)-1
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cos(t) = -12/13
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Therefore: cos(2t) = 2(-12/13)^2-1 = 0.7041
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Cheers,
Stan H.
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