Results 1 to 5 of 5

Math Help - Simplify- addition formulas trigo

  1. #1
    Member smmmc's Avatar
    Joined
    Jan 2009
    From
    House
    Posts
    80

    Simplify- addition formulas trigo

    Hey,
    cos(u-v)sinv + sin(u-v)cosv

    so
    cosu*cosv + sinu*sinv + sinu*sinv^2 + sinu*cosv^2 - cosu*sinv*cosv
    =..?


    Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Aug 2009
    Posts
    9
    I'm not entirely sure what you're looking for but when I worked this out I got:

    cos(u)cos(v)sin(v) + sin(u)sin(v)^2 + sin(u)cos(v)^2 - sin(v)cos(u)cos(v) = sin(u)(cos(v)^2 + sin(v)^2) = sin(u)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member smmmc's Avatar
    Joined
    Jan 2009
    From
    House
    Posts
    80
    Hey that is right but

    how does this

    sin(u)(sinv^2+cosv^2)

    turn into to sinu.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Aug 2009
    Posts
    9
    sin(any variable)^2 + cos(any variable)^2 = 1

    This is the most important trig identity you'll ever learn. I'd prove this for you, but its 3 AM for me so here: Proofs of trigonometric identities - Wikipedia, the free encyclopedia.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Super Member malaygoel's Avatar
    Joined
    May 2006
    From
    India
    Posts
    648
    Quote Originally Posted by smmmc View Post
    Hey,
    cos(u-v)sinv + sin(u-v)cosv

    so
    cosu*cosv + sinu*sinv + sinu*sinv^2 + sinu*cosv^2 - cosu*sinv*cosv
    =..?


    Thanks
    Here is a simple answer:
    cos(u-v)sinv + sin(u-v)cosv
    Let u-v=m
    then,
    cos(m)sinv + sin(m)cosv
    =sin(m+v)
    =sin(u-v+v)
    =sinu
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Addition and Subtraction Formulas
    Posted in the Trigonometry Forum
    Replies: 13
    Last Post: March 16th 2010, 05:39 PM
  2. The Addition and subtraction Formulas
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: March 16th 2010, 05:31 PM
  3. Addition Formulas - Question
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: November 22nd 2009, 09:10 PM
  4. addition formulas of sin and cos to simplify
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: November 7th 2009, 12:24 PM
  5. Deriving addition formulas
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: March 20th 2009, 12:11 PM

Search Tags


/mathhelpforum @mathhelpforum