Results 1 to 6 of 6

Math Help - Functions of their graphs

  1. #1
    Newbie
    Joined
    Jul 2008
    Posts
    4

    Functions of their graphs

    F(x)= (x^2 + 2)/ (x + 4)

    a) What is the domain of f?
    b)List the x-intercepts, if any, of the graph of f.
    c)List the y-intercept, if there is one, of the graph of f.

    Thank you!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    o_O
    o_O is offline
    Primero Espada
    o_O's Avatar
    Joined
    Mar 2008
    From
    Canada
    Posts
    1,407
    (a) What x values can the function not have? Hint: Denominator = 0?

    (b)To find the x-intercept, notice that the y-coordinate will be equal to 0. So set f(x) = 0 and solve for x, i.e.:
    0 = \frac{x^{2} + 2}{x+4} (Can you even solve this? If not, what does that mean?)

    (c) To find the y-intercept, notice that the x-coordinate will be equal to 0. So replace each x with a 0 and solve for f(0).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jul 2008
    Posts
    4
    a) -4
    b) x-intercept = 0
    c) y-intercept = 1/2

    Are these values correct?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    o_O
    o_O is offline
    Primero Espada
    o_O's Avatar
    Joined
    Mar 2008
    From
    Canada
    Posts
    1,407
    Just to reiterate, what you got for (a) is the value you cannot have in your domain.

    All is correct except for (b).

    Remember that whatever you x-intercept is, it will have a y-coordinate of 0. If you plug in x = 0 into f(x), do you get 0?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jul 2008
    Posts
    4
    B) would the answer be undefined?

    Thanks.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    o_O
    o_O is offline
    Primero Espada
    o_O's Avatar
    Joined
    Mar 2008
    From
    Canada
    Posts
    1,407
    Not undefined. Just that it doesn't exist! Since you can't find a solution, it means your graph doesn't have a x-intercept.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Sum of two functions (graphs)
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: July 18th 2011, 07:26 PM
  2. functions & graphs
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: May 7th 2010, 01:24 PM
  3. Functions and graphs
    Posted in the Calculus Forum
    Replies: 3
    Last Post: January 16th 2009, 10:26 AM
  4. Functions and their graphs
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: December 16th 2008, 10:50 PM
  5. Functions and graphs
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: September 2nd 2008, 04:36 PM

Search Tags


/mathhelpforum @mathhelpforum