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!

Homework Help: Factoring Cosine

  1. Sep 27, 2015 #1
    The Question:

    My Attempt:

    I use the 'Double Angle Formula' to get to the second line. Then multiply the sigma-x into whats in the brackets, then factor out at the end. I'm not sure how I reach the answer thats provided with the solution. Any help would be appreciated.

    Thank You.
  2. jcsd
  3. Sep 27, 2015 #2


    User Avatar
    Gold Member

    You've pretty much already got the answer. Just expand that last line and re-arrange.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted