Results 1 to 2 of 2

Math Help - Prove the identity

  1. #1
    Junior Member
    Joined
    Sep 2009
    Posts
    43

    Prove the identity

    How do I prove that:

    2sin^-1(x)=cos^-1 * (1-2x^2) x>=0
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member redsoxfan325's Avatar
    Joined
    Feb 2009
    From
    Swampscott, MA
    Posts
    943
    Quote Originally Posted by Asuhuman18 View Post
    How do I prove that:

    2sin^-1(x)=cos^-1 * (1-2x^2) x>=0
    Try proving that \cos(2\sin^{-1}x)=1-2x^2.

    This identity will help: \cos2\theta=1-\sin^2\theta
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. prove identity help!
    Posted in the Trigonometry Forum
    Replies: 7
    Last Post: December 2nd 2010, 10:00 AM
  2. prove the identity
    Posted in the Algebra Forum
    Replies: 3
    Last Post: June 7th 2010, 05:03 PM
  3. Prove this identity?
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: April 5th 2010, 05:29 PM
  4. Prove that each of the following is an identity
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: April 18th 2009, 02:39 PM
  5. Prove the Identity
    Posted in the Trigonometry Forum
    Replies: 10
    Last Post: February 25th 2008, 05:29 PM

Search Tags


/mathhelpforum @mathhelpforum