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Math Help - How can i find the angle X

  1. #1
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    How can i find the angle X

    [a*cos(b-X)]^2 = c*cos(X) where a,b,c are constant
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  2. #2
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    Re: How can i find the angle X

    Hey Yasir.

    Are you familiar with numerical root finding procedures?
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  3. #3
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    Re: How can i find the angle X

    Hi NO i am not familiar with it, how ever i can look for it. Is there any other way to solve this?

    Thanks
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  4. #4
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    Re: How can i find the angle X

    You should try expanding everything taking into account that cos(a-b) = cos(a)cos(b) - sin(a)sin(b).

    You may be able to get a quadratic equation in u where u = cos(x) and then solve for u and then for x.
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  5. #5
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    Re: How can i find the angle X

    Alternatively, assume that [a*cos(b-X)]^2 = c*cos(X) = k. That gives 2 equations [a*cos(b-X)]^2 = k and c*cos(X) = k.
    The first one gives cos(b-x ) = √k/a That is x =b - arscos√k/a
    and the second one gives x = arc cos √k/c
    There after find the common solution
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  6. #6
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    Re: How can i find the angle X

    Thanks a lot for your help. I am trying to solve this its not as simple as it looks like e.g. i am not able to find quadratic equation with only cos(x) term.
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