Results 1 to 4 of 4

Math Help - domain and range question

  1. #1
    Newbie
    Joined
    Oct 2007
    Posts
    2

    domain and range question

    if the paper says: Domain = reals, then isn't the range also {y: y= reals}?

    thanks

    please! this is urgent
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by kruton View Post
    if the paper says: Domain = reals, then isn't the range also {y: y= reals}?

    thanks
    no. it depends on the question. the domain and the range are two different things, they are not always equal.

    for instance, for y = x^2, the domain is all real x, but the range is all real y that are greater than or equal to zero. so dom(y) = ( -\infty, \infty) and ran(y) = [0, \infty)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2007
    Posts
    2
    the function is y=-5-2X

    domain = reals

    range = y greater than or equal to 0

    is that right?

    but why can't y be less than zero?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by kruton View Post
    the function is y=-5-2X

    domain = reals

    range = y greater than or equal to 0

    is that right?

    but why can't y be less than zero?
    no. the range is all reals as well. like i said IT DEPENDS ON THE PROBLEM. the answers i gave you before were for y = x^2. this is a line, it is different
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Domain and Range question
    Posted in the Pre-Calculus Forum
    Replies: 5
    Last Post: October 16th 2011, 12:39 PM
  2. Tricky Domain and Range Question
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: October 11th 2010, 05:28 PM
  3. Trigonometric and domain/range question.
    Posted in the Pre-Calculus Forum
    Replies: 10
    Last Post: September 16th 2010, 05:25 AM
  4. Replies: 6
    Last Post: September 16th 2009, 07:25 AM
  5. Domain & Range Question
    Posted in the Calculus Forum
    Replies: 6
    Last Post: March 20th 2008, 12:37 PM

Search Tags


/mathhelpforum @mathhelpforum