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: Solving trig equations using Addition formula

  1. Dec 4, 2011 #1
    1. The problem statement, all variables and given/known data

    Solve the equation: sin(x+∏/6)=2cosx for 0≤x≤2∏

    2. Relevant equations


    3. The attempt at a solution



    How do I solve from here?
  2. jcsd
  3. Dec 4, 2011 #2
    Moved the thread to precalc. Please post in the correct forum next time.
  4. Dec 4, 2011 #3

    I like Serena

    User Avatar
    Homework Helper

    Hi studentxlol! :smile:

    Perhaps you can use the following trig identity?

    a sin x + b cos x = √(a2+b2) sin(x+ϕ)

    where cos ϕ = a/√(a2+b2)
    and sin ϕ= b/√(a2+b2)
  5. Dec 5, 2011 #4


    User Avatar
    Science Advisor

    The first, obvious, step is to subtract (1/2) cos(x) from both sides. Then get a tangent.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook