Results 1 to 3 of 3

Math Help - function probelm

  1. #1
    Junior Member
    Joined
    Mar 2008
    Posts
    55

    function probelm

    Hey guys having some trouble with these ones still.

    Find the domain of f(x) = -12 / (-9 + x^2)

    Find the range of f(w) = 3 / (\sqrt{w} - 8)

    Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    Quote Originally Posted by smplease View Post
    Hey guys having some trouble with these ones still.

    Find the domain of f(x) = -12 / (-9 + x^2)

    Find the range of f(w) = 3 / (\sqrt{w} - 8)

    Thanks
    1.
    x can take any number except -3 and 3 since x = -3 and x=3 would make the denominator equal to zero (-9+9=0) and the division by zero is not allowed in mathematics. Hence the domain in interval notation is given by

    (-\infty, -3) \cup (-3,3) \cup (3, \infty)

    Note that neither -3 nor 3 are included in the domain..
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    Quote Originally Posted by smplease View Post
    Hey guys having some trouble with these ones still.

    Find the domain of f(x) = -12 / (-9 + x^2)

    Find the range of f(w) = 3 / (\sqrt{w} - 8)

    Thanks
    to find the range, you have:

     y= f(w) = \frac{3}{(\sqrt{w} - 8)}

    so,  (\sqrt{w} - 8) = \frac{3}{y}

    so,  \sqrt{w} = {\frac{3}{y}}+8

    thus,  w = ({{\frac{3}{y}}+8})^2

    y can take any number except 0 since y = 0 would make the denominator equal to zero and the division by zero is not allowed in mathematics. Hence the range in interval notation is given by:

    (-\infty,0) \cup (0,\infty)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Quadratic function probelm
    Posted in the Algebra Forum
    Replies: 2
    Last Post: March 26th 2010, 04:56 AM
  2. Matrix Probelm
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 16th 2009, 02:35 AM
  3. equality probelm
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 19th 2009, 08:19 AM
  4. Word probelm help!!!
    Posted in the Algebra Forum
    Replies: 2
    Last Post: April 15th 2009, 03:52 PM
  5. great probelm
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: January 9th 2009, 01:19 PM

Search Tags


/mathhelpforum @mathhelpforum