SOLUTION: Given cos(alpha) = 6/7, 0 < alpha > pi/2, find the exact value of cos(alpha/2)

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Question 812506: Given cos(alpha) = 6/7, 0 < alpha > pi/2, find the exact value of cos(alpha/2)
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Given cos(alpha) = 6/7, 0 < alpha > pi/2,
find the exact value of cos(alpha/2)
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cos(a/2) = sqrt[(1+cos(a))/2]
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Your Problem:
cos(a/2) = sqrt[(1+(6/7))/2] = sqrt[(13/7)/2] = sqrt(13/14)
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Cheers,
Stan H.