Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Solve Trigonometric Equation

  1. Feb 21, 2009 #1
    Can anyone help solve the below for 'a'


    I've reduced it to



    Which I think is right, but I can't get any further without just ending up with different forms that appear more complex.
  2. jcsd
  3. Feb 21, 2009 #2

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What makes this equation tough is the fact that you've got 2 different trig functions running around there. What's more you've got 2 different arguments in your cosine functions. I would try to express everything in terms of [itex]\cos(a)[/itex], so that you end up with a polynomial equation in that quantity.

    Try to make use of the following identities:



    I don't think you're going to get a closed form expression for a, but if you have numerical values for the parameters you will be able to get approximate solutions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook