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Need some Trig help, please.

  1. Oct 13, 2006 #1
    Ok, we'll basically we have two different functions and we're told to set them equal and then algebracially solve them for T.

    Here are the functions:

    y = 20 sin(pie/15 t) + 25

    y = -10cos(2pie/15 t) + 12

    It gives a hint and says to use a double-angle forumla and the quadratic forumla to help if needed.

    Does anyone have any idea on where to start? I'm totally confused.

    Thanks a lot!
  2. jcsd
  3. Oct 13, 2006 #2


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    y = -10Cos(2pi/15 t) + 12
    y = -10({Cos(pi/15t)}^2 - {Sin(pi/15t)}^2) + 12

    From here it is pretty obvious what to do, get the expression in terms of Sin and solve for Y.
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