1. Limited time only! Sign up for a free 30min personal 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!

Sum of square cosines

  1. Dec 3, 2009 #1
    I'm looking for a way to change a finite sum of square cosines:

    [tex]\Sigma^{N}_{s=1}cos^{2}(x_{s})[/tex]

    into a single function of the sum of x:

    [tex]f(\Sigma^{N}_{s=1}x_{s})[/tex]

    Is there a known way to do this, even if with an approximate method (i.e. Taylor series or such)?. It's ok if it just works in a [tex]\pi[/tex] range.
     
  2. jcsd
  3. Dec 3, 2009 #2
    Can't be done. If [itex]N=2, x_1=0, x_2=\pi[/itex], sum of x is [itex]\pi[/itex] and sum of cosines is 2. IF [itex]N=2, x_1=\pi/2, x_2=\pi/2[/itex], sum of x is still [itex]\pi[/itex], but sum of cosines is 0.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Sum of square cosines
  1. Sum of cosines (Replies: 6)

Loading...