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: Inverse trig function

  1. Mar 4, 2010 #1
    1. The problem statement, all variables and given/known data
    Find the exact value of the expression:

    2. Relevant equations

    3. The attempt at a solution
    I know you're supposed to use sin2x=2sinxcosx somehow but not sure how to start.
  2. jcsd
  3. Mar 4, 2010 #2


    Staff: Mentor

    Start by letting u = arcsin(3/5). Then your expression is sin(2u) = ?

    It will be helpful to draw a right triangle where u is one of the acute angles. Label the sides and hypotenuse so that sin(u) = 3/5.
  4. Mar 4, 2010 #3
    Ah, OK! 24/25 correct?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook