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!

Solving Equations Using Trigonometric Identities

  1. Nov 10, 2012 #1
    Hey PF!

    1. The problem statement, all variables and given/known data
    Find exact solutions for the following equations over the domain 0 ≤ x <2π
    2sinx = 3 + 2cscx

    2. Relevant equations
    sin2+cos2=1

    3. The attempt at a solution
    2sinx = 3 + 2cscx
    2sinx = 3 +2(1/sinx)
    sinx = 3/2 + 1/sinx
    sinx - 1/sinx = 3/2
    (1-1-cos2x)/sinx = 3/2
    -cos2x/sinx = 3/2
    cos2x/sinx = -3/2

    I am perplexed by this question. Where do I go from here? How do I solve this equation?
     
  2. jcsd
  3. Nov 10, 2012 #2

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    No need to change sin2(x) into 1-cos2(x) .

    Multiply both sides of sin(x) = 3/2 + 1/sin(x) by sin(x) .
     
  4. Nov 10, 2012 #3
    Ahhhh... Thank you for elucidating me. I can see now that I have to factor and solve for x. Thank you again for your help!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Solving Equations Using Trigonometric Identities
Loading...