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Math Help - Solve for theta

  1. #1
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    Solve for theta

    25sin@ -1.5 cos@ = 20 @ = theta
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  2. #2
    Rhymes with Orange Chris L T521's Avatar
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    Quote Originally Posted by jewd777 View Post
    25 sin@ -1.5 cos@ = 20, whats @ = ?
    Hint: Apply the identity A\cos\theta+B\sin\theta=\sqrt{A^2+B^2}\cos\!\left(  x-\tan^{-1}\!\left(\tfrac{B}{A}\right)\right)
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  3. #3
    MHF Contributor Calculus26's Avatar
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    there may be a more clever way but by brute force and ignorance:
    Solve for 25 sin(@) = 20+1.5cos(@)

    square both sides and convert the LHS to a fn of cos(@)

    you now have a quadratic in cos@
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