Results 1 to 2 of 2

Math Help - Solve [0,2pi)

  1. #1
    Newbie
    Joined
    Jul 2012
    From
    U.S
    Posts
    10

    Solve [0,2pi)

    2 similar problems that are really challenging for me.


    1) solve [0,2pi) sin 2x-sinx = 0

    2) solve [0,2pi) tan^2x sinx= tan^2x



    Also how do i rewrite cos^3 x so that it does not contain power greater than 1? I don't think i can use double angle identity since it has power of 3.. not multiples of 2



    Thanks!!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Amer's Avatar
    Joined
    May 2009
    From
    Jordan
    Posts
    1,093

    Re: Solve [0,2pi)

    \sin 2x - \sin x = 0
    use the identity \sin 2x = 2\sin x \cos x , then take as a factor sinx

    \sin x (2 \cos x - 1 ) = 0

    \sin x = 0 \Rightarrow x = 0,\pi,2\pi

    2\cos x - 1 = 0 \Rightarrow \cos x = \frac{1}{2}\;\Rightarrow x = \frac{\pi}{3},\frac{5\pi}{3}

    second one move the left side to the right side then take as a factor tan^2 x same strategy above
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Solve for x...
    Posted in the Algebra Forum
    Replies: 3
    Last Post: November 17th 2010, 05:49 PM
  2. need to solve summation equation to solve sum(x2)
    Posted in the Statistics Forum
    Replies: 2
    Last Post: July 16th 2010, 11:29 PM
  3. Replies: 1
    Last Post: June 9th 2009, 11:37 PM
  4. solve for x...
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 30th 2009, 11:50 PM
  5. Solve: x^5 - x = 0
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 26th 2009, 08:34 PM

Search Tags


/mathhelpforum @mathhelpforum