Results 1 to 3 of 3

Math Help - Exact value of sin-1(sin(7(pi/2))

  1. #1
    Junior Member
    Joined
    Sep 2009
    Posts
    34

    Exact value of sin-1(sin(7(pi/2))

    Hi, its me again. Hope I'm not asking too many math questions.
    I know f( f^-1(x)) = x but is it the same for f^-1(f(x)) ?/

    If it is; sin^ -1(sin(7(pi/2))) = 7pi/2 ?

    Thanks !
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member pacman's Avatar
    Joined
    Jul 2009
    Posts
    448
    if you are in doubt, check it with a calculator,

    "sin^ -1(sin(7(pi/2))) = 7pi/2"
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by pacman View Post
    if you are in doubt, check it with a calculator,

    "sin^ -1(sin(7(pi/2))) = 7pi/2"
    The range of the inverse sin function is, by definition, [-pi/2, pi/2]. Since sin(7 pi/2) = -1 it follows that \sin^{-1} \left(\sin \left( \frac{7 \pi}{2} \right) \right) = \sin^{-1} (-1) = - \frac{\pi}{2}.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 5
    Last Post: September 21st 2011, 01:12 AM
  2. to be exact or not exact? this is the question...
    Posted in the Differential Equations Forum
    Replies: 2
    Last Post: February 5th 2011, 09:56 AM
  3. Why are exact ODEs called exact?
    Posted in the Differential Equations Forum
    Replies: 6
    Last Post: December 27th 2009, 10:48 AM
  4. exact value
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 27th 2009, 05:40 PM
  5. Exact value of sin
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: October 9th 2008, 05:41 PM

Search Tags


/mathhelpforum @mathhelpforum