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Math Help - Sine/ Cosine. solve for x

  1. #1
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    Sine/ Cosine. solve for x

    Solve for x
    A. sin30=x/12
    b. cos136
    =5/x
    c. sin5
    =26/x
    d sin x=5/12
    e. cos x=2/15

    i need help.
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  2. #2
    MHF Contributor
    Joined
    Apr 2008
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    You're going to need a calculator for four of these. The first is elementary:

    \sin 30 = \frac{x}{12}

    x = 12 \sin 30 = 12(0.5) = 6

    For b and c: rearrange the equation.

    For example,
    x = \frac{5}{\cos 136}

    Then it's plug and chug.

    d and e are similar.

    For d:
    x = \sin^{-1}(5/12)

    You have no choice but to use the calculator on both of these. Note that \sin^{-1} is the inverse sine function.
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  3. #3
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    thank you
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