Question 454727: if tanA= 5/12, find sin2a
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! if tanA= 5/12, find sin(2a)
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If tan(A) = 5/12, y = 5 when x = 12
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Then r = sqrt[5^2+12^2] = sqrt[169] = 13
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So, sin(A) = y/r = 5/13
and cos(A) = x/r = 12/13
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Therefore sin(2A) = 2*sin(A)*cos(A) = 2*(5/13)(12/13) = 120/169 = 0.7101
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Cheers,
Stan H.
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