Results 1 to 2 of 2

Math Help - Simple Neg-Angle ID question.

  1. #1
    Junior Member
    Joined
    Oct 2008
    Posts
    39

    Simple Neg-Angle ID question.

    I know that the Identity is, Cos(-theta) = Cos theta. So, if Cos Theta = -.65, then Cos (-theta) = -.65.......My original answer was Cos (-theta) = .65.......Not sure why it is -.65. Could someone steer me in the right direction here. Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,056
    Thanks
    894
    Quote Originally Posted by Brndo4u View Post
    I know that the Identity is, Cos(-theta) = Cos theta. So, if Cos Theta = -.65, then Cos (-theta) = -.65.......My original answer was Cos (-theta) = .65.......Not sure why it is -.65. Could someone steer me in the right direction here. Thanks
    \cos(\theta) = \cos(-\theta) because the cosine function is even.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: May 4th 2010, 10:08 AM
  2. Simple double angle formulae
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 20th 2010, 11:21 AM
  3. Replies: 3
    Last Post: September 20th 2009, 05:11 PM
  4. Replies: 2
    Last Post: March 28th 2009, 03:18 PM
  5. Replies: 5
    Last Post: February 12th 2008, 09:54 PM

Search Tags


/mathhelpforum @mathhelpforum