1. Not finding help here? Sign up for a free 30min 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!

Math 110

  1. Nov 20, 2008 #1
    1. Find the exact value of the expression arcsin(sin(5pi/9))

    2. 5pi/9 = 100 degrees and pi/9 = 20 degrees

    3. Tried pi/9 but it is wrong
  2. jcsd
  3. Nov 21, 2008 #2
    SO, 5pi/9 is 100 degree. So take sin of that. And do the arc sin of that.
    Sin(5pi/9) = .9848

    arcsin(.9848) = 80 degrees
  4. Nov 21, 2008 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    Because sine is periodic, it doesn't have a true "inverse". The usual definition of Arcsine gives a value between [itex]-pi/2[/itex] and [itex]\pi/2[/itex]. [itex]5\pi/9[/itex] is not in that range. Use the facts that [itex]sin(x+ 2\pi)= sin(x)[/itex] and [itex]sin(\pi- x)= - sin(x)[/itex].
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Math 110
  1. Math manipulation (Replies: 3)

  2. Series Maths (Replies: 3)

  3. Discrete Math (Replies: 1)

  4. Math problem (Replies: 6)

  5. Math Task (Replies: 20)