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-   -   Inverse functions/ unit circle (https://www.askmehelpdesk.com/showthread.php?t=160736)

  • Dec 8, 2007, 04:38 PM
    Psychiccleo21
    Inverse functions/ unit circle
    How do I solve this?

    Question: Use inverse functions where needed to find all solutions of the equation in the interval [0, 2 pi)

    3tan^2x - 11sec x + 13 = 0
  • Dec 8, 2007, 04:44 PM
    s_cianci
    Start by changing everything to sin and cos. Then combine everything into 1 single rational expression. It falls into place from there.
  • Dec 8, 2007, 05:29 PM
    galactus
    Another way is to remember that

    Then we have:





    Now, let

    We get:

    Now, solve the quadratic.
  • Dec 8, 2007, 07:37 PM
    Psychiccleo21
    Quote:

    Originally Posted by Psychiccleo21
    How do i solve this?

    Question: Use inverse functions where needed to find all solutions of the equation in the interval [0, 2 pi)

    3tan^2x - 11sec x + 13 = 0

    I had it figured up to the point where I had cos x = 3/5 and cos x = 1/2, but after that, I had no idea what to do. I know I can find the points where cos = 1/2 by looking on a unit circle, but 3/5..

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