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: Trig solve for all angles x problem

  1. Apr 19, 2010 #1
    1. The problem statement, all variables and given/known data
    Sin(x)+sin(2x)+sin(x)*Cos(2x)+sin(2x)*cos(x)=0
    Solve for all angles x.


    2. Relevant equations
    Sin(2x)= 2sin(x)*cos(x)

    3. The attempt at a solution
    Not really sure what to do. I noticed that i could maybe factor out Sin(x), but i do not really know if that is right.

    I seem to be always stuck on these kind of problems. Any general tips would greatly help me as well. Thank you
     
  2. jcsd
  3. Apr 19, 2010 #2
    Last edited by a moderator: May 4, 2017
  4. Apr 19, 2010 #3
    So you just used double angles to get rid of sin(2x) and cos(2x)?
     
  5. Apr 19, 2010 #4
    Yes I used double angles for them and I had to use the cos^2 identity also. I wish I could just scan my paper and upload it but no scanner.
     
  6. Apr 20, 2010 #5
    Cool, i think i got it now. Thanks for your time.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook