1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can addition formula be applied to more than 2 sums?

  1. Oct 17, 2009 #1
    1. The problem statement, all variables and given/known data

    Not an actual problem, but to help solve my homework, would cos(A+B+C)=
    CosACosBCosC-SinASinBSinC (Cos(x+y)=cosxcoxy-sinxsiny)

    I was unsure if this can be applied to multiple digits or only 2.



    I know I could plug in numbers to test, but I was wondering about the logic behind this.
     
  2. jcsd
  3. Oct 17, 2009 #2

    Mark44

    Staff: Mentor

    No, that's not it.

    Expand cos((A+B) + C) first, and then expand the factors with cos(A+B) and sin(A+B).
     
  4. Oct 17, 2009 #3
    I see.

    So Cos(A+B+C) =

    cos((CosAcosB-sinAsinB)+C)

    then use the value from the first portion in another addition formula with C?
     
  5. Oct 18, 2009 #4

    Mark44

    Staff: Mentor

    Yep.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Can addition formula be applied to more than 2 sums?
Loading...