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!

Trig functions, finding co-ordinates

  1. Sep 24, 2012 #1
    1. The problem statement, all variables and given/known data

    I have a graph with the functions f(x)=sin2x and g(x)=cosx. The 2 graphs intersect at point B. They want me to find the co-ordinates of B.

    2. Relevant equations

    3. The attempt at a solution

    Must I equate the two graphs?

    sin2x = cosx
    2x = 90-x, 3x = 90, x=30 or 2x = 180-(90-x), x=90

    It doesnt seem right, is their any other steps?
  2. jcsd
  3. Sep 24, 2012 #2
    Aren't you given any specific range within which you want the solution, both the graphs intersect at many points.
  4. Sep 24, 2012 #3
    they say that f and g intersect at A(30:0.87) and B.
    the domain is xE[0;270].
    Thats all that is given.
  5. Sep 24, 2012 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Do you know a trig identity for sin(2x)?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Trig functions, finding co-ordinates
  1. Finding co-ordinate (Replies: 6)

  2. Polar co-ordinates (Replies: 11)