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AonZ

  • 2 years ago

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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  1. AonZ
    • 2 years ago
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    @phi @primeralph @ganeshie8

  2. primeralph
    • 2 years ago
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    |dw:1368828851468:dw|

  3. primeralph
    • 2 years ago
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    |dw:1368828916634:dw|

  4. primeralph
    • 2 years ago
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    |dw:1368828952238:dw|

  5. AonZ
    • 2 years ago
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    isnt cosA = 4/5? not cos2A?

  6. primeralph
    • 2 years ago
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    no, I changed theta = 2A, so costheta = cos2A

  7. AonZ
    • 2 years ago
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    oh :P didnt know you could do that! Thanks so much!!!

  8. primeralph
    • 2 years ago
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    you can.

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