Re: Mimicking the TI calculator graph "trace" function
- To: mathgroup at smc.vnet.net
- Subject: [mg113212] Re: Mimicking the TI calculator graph "trace" function
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Tue, 19 Oct 2010 05:54:26 -0400 (EDT)
- Reply-to: hanlonr at cox.net
Don't know anything about the calculator but this may be close to what you want:
f[x_] := (x + 2) (x - 1) (x - 3)
Manipulate[
Module[{fp, pt, xdel = 0.1, xmin = -3, xmax = 4},
Plot[f[x], {x, xmin, xmax},
Frame -> True,
Epilog -> {Text[
{p, NumberForm[fp = f[p], 3]},
pt = {p, fp},
{If[p < (xmax + xmin)/2, -1.5, 1.5],
If[fp < 0, -1, 1]}],
If[fp == 0 ||
Abs[f'[p]] < Abs[f'[p - xdel]] &&
Abs[f'[p]] < Abs[f'[p + xdel]],
Directive[AbsolutePointSize[6], Red],
Directive[AbsolutePointSize[4], Blue]],
Point[pt]}]],
{{p, -3, x}, -3, 4, 0.1,
Appearance -> "Labeled"}]
Bob Hanlon
---- John Accardi <accardi at accardi.com> wrote:
=============
Hello ....
I'm trying to find the easiest way to get Mathematica to do what a TI-84
calculator does with the "trace" button on a graph. (displays x,y
coordinates at tracing cursor positions). Alternately, I could live
with having the intersection point(s) of two graphs dynamically display,
with label(s), on a plot, along with the function graphs. I know I can
do this in a table of values, but I want to see point and label on the
graph plot.
This document describes much of it, but you have to hard code the
solution point to create the point label:
http://amath.colorado.edu/computing/Mathematica/labelpoints/
(The above document contains a link to the *.nb being described.)
I guess I am looking for any code that exists where the point label is
created dynamically after a solution point is calculated and included in
the plot.
This seems like a very common thing to want to do but I cannot seem to
find anything in the archive/forum that does anything like this.
Thanks for any insights.
Gianni
--
Bob Hanlon