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Math Help - Theory questions using laws of trig

  1. #1
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    Theory questions using laws of trig

    Hey all, I have a theory question using Trig Laws (and need to know if i'm right)

    Q: To find the two possible values of cos(x) from a given value of sin(x) you would use??

    my answ: The sum and difference of angles;
    ie/ sin(A+B) = sinAcosB+cosAsinB
    or sin(A-B)=sinAcosB-cosAsinB

    is that right?

    also- just to be sure- AAA (given three angles..) You can't find a side of a triangle right?

    Thanks guys!!
    -Brittany
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  2. #2
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    Q: To find the two possible values of cos(x) from a given value of sin(x) you would use??

    \cos^2{x} = 1 - \sin^2{x}

    \cos{x} = \pm \sqrt{1 - \sin^2{x}}
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