Printable View
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
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.
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)
http://i7.photobucket.com/albums/y284/wrf01a/graph1.jpg
Without access to an equation editor, my previous post might be confusing
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!).
Yay!
That's what I was looking for. It's been awhile since I've done this kind of thing.
Jeff Eff