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Re: [Fathom & TP] Evaluation Error message
Posted:
Jun 7, 2008 2:05 AM


On Jun 6, 2008, at 11:43 AM, JCHAPPELLE@BROOKSTONEschool.org wrote:
> I am attempting to write a demonstration of power transformations to > achieve linearity. I have created a data set with x defined as > random integers from 5 to 5. The equation for y is (a(xc)^p+d)^t > with all variables controlled by sliders. Whenever x is a negative > number I get an evaluation error for y. Understand that when p is a > fraction with an even denominator and xc is negative there is no > solution but when I set p and t to integer values the left side of > the parabola does not appear. I'm sure I'm doing something stupid > but I just cannot see it. Can anyone help.
When I tried it, at first I had the same experience. But then I noticed I had set p to 2 and t was still at its default 5. This was not the problem! The problem was that d was so large that the function was outside the window. (I have made this mistake countless times, so I hope it's the one you made too!)
So set a = 1, c = 0, d = 0, and see if you can see the function.
With high hopes, Tim
 Tim Erickson * Epistemological Engineering 5269 Miles Avenue, Oakland CA 94618 * 510.653.3377 http://www.eeps.com
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