Question 859668: Find the exact values of sin 2u , Cos 2u, and tan 2u using double angle formulas.
1. csc u= 3, pi/2 < u > pi
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Find the exact values of sin 2u , Cos 2u, and tan 2u using double angle formulas.
1. csc u= 3, pi/2 < u > pi; QII where x is negative and y is positive.
sin(u) = 1/3; y = 1 and r = 3
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x = -sqrt[9-1] = -sqrt(8)
cos(u) = -sqrt(8)/3 = -(2/3)sqrt(2)
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tan(u) = y/x = -1/sqrt(8)
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Your Problems:
sin(2u) = 2sin(u)cos(u) = 2[1/3][-sqrt(8)/3]
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cos(2u) = cos^2(u)-sin^2(u)
etc.
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tan(2u) = [2tan(u)]/[1-tan^2(u)]
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Cheers,
Stan H.
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