Results 1 to 4 of 4

Math Help - Prove the composite argument property for cos(A-B)

  1. #1
    Member wiseguy's Avatar
    Joined
    Jul 2010
    Posts
    101

    Prove the composite argument property for cos(A-B)

    "Show numerically that the composite argument property for cos (A - B) is correct by substituting 37 for A and 21 for B and showing that you get the same answer for both sides of the equation."


    My response is:

    cos(37-21)=cos(16)=-0.9576594803<br /> <br />
cos(37-21)=cos(37)-cos(21) does not equal -0.9576594803

    I'm just wondering if I answered the question... the point is that cosine does not distribute.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    I think you are supposed to use the fact that \cos(a-b) = \cos a \cos b +\sin a \sin b
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member wiseguy's Avatar
    Joined
    Jul 2010
    Posts
    101
    So cos(37-21)=cos37cos21+sin37sin21 would suffice?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    That's my understanding of the question.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Composite argument property
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: July 26th 2010, 10:46 AM
  2. [SOLVED] Double argument property?
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: July 24th 2010, 10:14 AM
  3. [SOLVED] Composite argument property and linear combination of cosx/sinx
    Posted in the Trigonometry Forum
    Replies: 10
    Last Post: July 22nd 2010, 08:13 PM
  4. Prove/disprove using logical argument
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: February 22nd 2010, 10:45 PM
  5. how can u prove this argument
    Posted in the Calculus Forum
    Replies: 4
    Last Post: October 19th 2008, 06:56 PM

/mathhelpforum @mathhelpforum