Results 1 to 6 of 6

Math Help - Is there an equation?

  1. #1
    Newbie
    Joined
    Apr 2006
    Posts
    2

    Is there an equation?

    I hope I can describe this well enough so that someone might be able to help me.

    I'm looking for a general equation that includes, for example, the following coordinates:

    (0,0)
    (1,1)
    (3,2)
    (6,3)
    (10,4)

    I've figured out two ways to describe what I want. Either x = the sum of all y's less than or equal to it, or x = y plus the x immediately preceding it in the series.

    I'd be most interested in whether this could be graphed as a curve.

    Thanks in advance, and I hope this is clear.

    Jeff Eff
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Oct 2005
    From
    Earth
    Posts
    1,599
    Both of your explanations work, but I don't think you'll be able to graph those kinds of "functions" on any graphing utility because they are not standard ones, like sin(x), ln(x), sqrt(x), etc.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member Ranger SVO's Avatar
    Joined
    Apr 2006
    From
    Abilene Tx
    Posts
    90
    I think you can. Gragh the following equation

    f (x) = [sqrt(8*x+1)-1] / 2

    If you look at your points, you should be able to see a quadratic equation only in reverse. (0,0) (1,1) (2,3) (3,6) (4,10)

    The equation should be y = 0.5x *(x + 1), now solve for x and you should get what you want to graph

    If you want the other half of the graph you will also have to graph -f(x)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member Ranger SVO's Avatar
    Joined
    Apr 2006
    From
    Abilene Tx
    Posts
    90


    Without access to an equation editor, my previous post might be confusing
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Oct 2005
    From
    Earth
    Posts
    1,599
    Oh nice catch! I didn't mean that there wasn't an answer, just that the two explanations the OP gave couldn't be graphed in that way on something like you did - the TI-89 (good calculator!).
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Apr 2006
    Posts
    2

    Thank You!

    Yay!

    That's what I was looking for. It's been awhile since I've done this kind of thing.

    Jeff Eff
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: April 11th 2011, 01:17 AM
  2. Partial differential equation-wave equation - dimensional analysis
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: August 28th 2009, 11:39 AM
  3. Replies: 2
    Last Post: May 18th 2009, 12:51 PM
  4. Replies: 2
    Last Post: April 28th 2009, 06:42 AM
  5. Replies: 1
    Last Post: October 23rd 2008, 03:39 AM

Search Tags


/mathhelpforum @mathhelpforum