Results 1 to 2 of 2

Math Help - cos identities

  1. #1
    Member
    Joined
    Sep 2009
    Posts
    98

    cos identities

    Solve the Equation for A between 0 and 360 inclusive, giving non-exact answers. In each case use trigonometric identities.

    a) cos2A +3 +4cosA=0

    b) 2cos 2A+1+ sinA= 0

    THANKS!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Oasis1993 View Post
    Solve the Equation for A between 0 and 360 inclusive, giving non-exact answers. In each case use trigonometric identities.

    a) cos2A +3 +4cosA=0

    b) 2cos 2A+1+ sinA= 0

    THANKS!
    HI

    (1) 2\cos^2 A-1+4\cos A+3=0

    2\cos^2 A+4\cos A+2=0

    \cos^2 A+2\cos A+1=0

    \cos A=-1

    go on ....

    (2) 2(1-\sin^2 A)+1+\sin A =0
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 6
    Last Post: June 23rd 2010, 12:59 AM
  2. Identities
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: March 7th 2010, 11:19 PM
  3. Identities
    Posted in the Trigonometry Forum
    Replies: 4
    Last Post: March 7th 2010, 06:39 PM
  4. set identities
    Posted in the Discrete Math Forum
    Replies: 5
    Last Post: April 12th 2009, 03:57 PM
  5. Identities help...
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: November 13th 2008, 08:30 AM

Search Tags


/mathhelpforum @mathhelpforum