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Math Help - Trig Identities

  1. #1
    Junior Member
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    Trig Identities

    Use an appropriate trigonometric identity and the information that sin 54=0.8090 to determine cos 36.

    Any help with this would be great thanks!
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  2. #2
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    Re: Trig Identities

    Remember cos(90-a ) = sin A
    cos 36 = cos ( 90-54) = sin 54
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  3. #3
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    Re: Trig Identities

    Thank you!
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