AonZ
Hard trig question. Please Please help!
if θ is an acute angle and cos θ = 4/5 . use the result cos^2 θ = (1 + cos2x) / 2 . Find the exact value of cos (θ/2)
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AonZ
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@phi @primeralph @ganeshie8
primeralph
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primeralph
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primeralph
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AonZ
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isnt cosA = 4/5? not cos2A?
primeralph
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no, I changed theta = 2A, so costheta = cos2A
AonZ
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oh :P didnt know you could do that! Thanks so much!!!
primeralph
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you can.