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Trig problem

  1. Jul 19, 2004 #1
    Hey everyone,
    I'm trying to solve for theta in a derivitive of a ballistics equation and I'm afraid I'm stuck. My trigonometry is a little rusty, can someone help me out? I have:


    With the information I'm given I can solve the the right side of the equation ending up with:

    cos(theta)*sin(theta)=some number

    How do I get theta by knowing what cos(theta)*sin(theta) equals?

  2. jcsd
  3. Jul 19, 2004 #2
    cos(t)sin(t) = 2sin(t)cos(t)/2 = sin(2t)/2. Now you can use arcsine...
  4. Jul 19, 2004 #3


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    Staff Emeritus
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    Just clarifying what Muzza wrote above...so there's no room for misunderstanding :

    [tex]cos(t)sin(t) = \frac {2sin(t)cos(t)}{2} = \frac {sin(2t)}{2}. [/tex]
  5. Jul 19, 2004 #4
    OK, thanks for the help!
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