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Thread: Finding value of sin(theta) from value of cos(theta).

  1. November 26th 2010, 07:46 PM #1
    SOHCAHTOA
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    Unhappy Finding value of sin(theta) from value of cos(theta).

    I've been staring at this question...for so long.

    if cos/theta = 1/3 , find the value of 6sin^2/theta - 6
    Last edited by mr fantastic; November 26th 2010 at 09:14 PM. Reason: Re-titled.
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  2. November 26th 2010, 07:47 PM #2
    Prove It
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    Use the Pythagorean Identity:

    \displaystyle \sin^2{\theta} + \cos^2{\theta} = 1.

    Substitute \displaystyle \cos{\theta} and then rearrange.
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  3. November 26th 2010, 07:51 PM #3
    SOHCAHTOA
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    Thanks for the tip!!
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