Results 1 to 2 of 2

Math Help - Equations Involving Multiple Angles

  1. #1
    Newbie
    Joined
    May 2011
    Posts
    12

    Equations Involving Multiple Angles

    Hi there,

    I'm currently revising for my higher exam, and am a bit confused as to how to solve this equation.

    sin2x-cosx=0 for 0≤x≤360

    I have managed to get 30 and 150 degrees, but the answers tell me I should also be getting 90 and 270 degrees, and I'm unsure how to go about getting those answers.

    Thanks in advance.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1
    Quote Originally Posted by HighlyFlammable View Post
    sin2x-cosx=0 for 0≤x≤360
    I have managed to get 30 and 150 degrees,
    \sin(2x)-\cos(x)=2\sin(x)\cos(x)-\cos(x)=\cos(x)(2\sin(x)-1)=0
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. integrals involving multiple e's
    Posted in the Calculus Forum
    Replies: 7
    Last Post: February 11th 2010, 09:40 AM
  2. multiple angles
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: November 29th 2009, 06:07 PM
  3. proof involving least common multiple
    Posted in the Number Theory Forum
    Replies: 5
    Last Post: October 28th 2009, 04:05 PM
  4. about multiple angles of trigonometry
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: August 2nd 2008, 06:58 PM
  5. multiple solutions to equations involving sine
    Posted in the Calculus Forum
    Replies: 2
    Last Post: February 1st 2008, 07:01 AM

Search Tags


/mathhelpforum @mathhelpforum