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-   -   sin^2x=cosx-1 (https://www.askmehelpdesk.com/showthread.php?t=603316)

  • Oct 12, 2011, 04:54 PM
    chels114
    sin^2x=cosx-1
    How do I solve this, answer in degrees?
  • Oct 13, 2011, 01:26 AM
    Unknown008
    You should have your basic identities with you, and one of them is:



    Use one of these and you would get something just like a quadratic equation to solve. That would be easy :)

    Can you post what you get? :)
  • Oct 13, 2011, 06:38 AM
    ebaines
    A minor correction: cos(2A) = 1 - 2 sin^2(A)

    However, here's another way: use sin^2(x) = 1 - cos^2(x), then apply the quadratic equation to solve for cos(x).
  • Oct 13, 2011, 06:50 AM
    Unknown008
    Oops, typo :o

    And somehow, I read it as sin squared 2x...

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