Re: piecewise graphs


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Re: piecewise graphs



Recent message traffic:

> >is there a way to graph piecewise functions on the TI-85?
> >piecewise as in:
> >f(x) = { x^2, x<0
> >         x+1, x>=1
> >and so on...
>
> yep.. type it like this
> (x^2)(x<0)+(x+1)(x>=1)
> then press GRAPH..

The problems that I have with the method suggested above is that it redefines
the piecewise function as a sum of two functions. Also, unless the graphing
mode is changed, an extraneous line appears on the graph.
Instead, graph the following
y1=(x^2)/(x<0)
y2=(x+1)/(x>=1)

This has the effect of making each piece undefined, except on its domain. This
is what is intended by the definition of  the piecewise defined function.
There is no need to change graphing modes.  Also, if graphed in the window
-12.6 < = x <= 12.6, you can trace and see that each piece of the function is
defined only on its domain, and that the function is undefined on the interval
[0,1)
------------------------------------------------------------------
Ben Sultenfuss <bsultenfuss@sfasu.edu>
Stephen F. Austin State University
Department of Mathematics and Statistics
1936 North Street, PO Box 13040, SFA Station
Nacogdoches, Texas 75962-3040
Voice: Office: 409-468-3805   Home: 409-560-5508
Fax: Office: 409-468-1669   Home: 409-560-0038
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----------
> From: n X t <nxt@JUNO.COM>
> To: CALC-TI@LISTS.PPP.TI.COM
> Subject: Re: piecewise graphs
> Date: Friday, November 14, 1997 16:54
>
> On Fri, 14 Nov 1997 15:19:54 -0500 Jeff <polarize@SOUTHEAST.NET> writes:
> >is there a way to graph piecewise functions on the TI-85?
> >piecewise as in:
> >
> >f(x) = { x^2, x<0
> >         x+1, x>=1
> >and so on...
>
> yep.. type it like this
>
> (x^2)(x<0)+(x+1)(x>=1)
>
> then press GRAPH..
> ---
> -nXt
>    nxt@geocities.com     http://nxt.home.ml.org  OR:
>    nxt@juno.com
> http://www.geocities.com/SiliconValley/Way/6521