Results 1 to 5 of 5

Math Help - Functions confusion

  1. #1
    Member
    Joined
    Sep 2012
    From
    US
    Posts
    123

    Exclamation Functions confusion

    Hi I just have no clue where to start for this questions :S

    Find the functions and their domains. (Enter the domains in interval notation.)

    f
    (x) = x + 1/x, g(x) = x+14/x+2


    (a) f g
    (f g)(x) =
    domain

    (b) g f
    (g f)(x) =
    domain

    (c) f f
    (f f)(x) =
    domain

    (d) g g
    (g g)(x) =
    domain
    Last edited by Oldspice1212; September 19th 2012 at 06:48 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Sep 2012
    From
    US
    Posts
    123

    Re: Functions confusion

    Also...
    Thanks a ton in advance

    Find each of the following functions.
    f(x) = 2 − 4x, g(x) = cos x
    (a) f of g


    State the domain of the function. (Enter your answer using interval notation.)


    (b) g of f


    State the domain of the function. (Enter your answer using interval notation.)


    (c) f of f


    State the domain of the function. (Enter your answer using interval notation.)


    (d) g of g


    State the domain of the function. (Enter your answer using interval notation.)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,842
    Thanks
    320
    Awards
    1

    Re: Functions confusion

    These a composition problems. What you need to do is to specify the two functions and "nest" one inside the other.

    For example, take f(x) = 3x + 2 and g(x) = \frac{1}{x}

    Then
    f \circ g(x) =  f(g(x)) = f \left ( \frac{1}{x} \right ) = 3 \left ( \frac{1}{x} \right ) + 2

    Give it a try. If you still have problems show us what you have tried and we'll work from there.

    -Dan
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Sep 2012
    From
    US
    Posts
    123

    Re: Functions confusion

    Thanks
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Jul 2012
    From
    Jaipur,Rajasthan
    Posts
    36
    Thanks
    1

    Re: Functions confusion

    You have to write these types of functions as f of g= f(g(x))
    Thus for any type of value you have to put the value of x step by step. for the first question
    (a) f of g=f(g(x))
    Here, f(x)=2-4x
    g(x)=cosx
    Therefore, f(g(x))=f((cosx))
    =>2-4cosx
    These types of questions are easy to solve. you can try the other three easily.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. DVs and IVs confusion
    Posted in the Statistics Forum
    Replies: 0
    Last Post: December 4th 2011, 02:09 AM
  2. Replies: 4
    Last Post: April 14th 2010, 07:45 PM
  3. confusion
    Posted in the Statistics Forum
    Replies: 2
    Last Post: August 15th 2009, 02:17 AM
  4. a confusion
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: November 24th 2008, 01:59 AM
  5. Confusion
    Posted in the Geometry Forum
    Replies: 2
    Last Post: October 21st 2006, 03:47 AM

Search Tags


/mathhelpforum @mathhelpforum