       Re: Plotting

• Subject: [mg2163] Re: Plotting
• From: ianc (Ian Collier)
• Date: Wed, 11 Oct 1995 05:58:20 GMT
• Approved: usenet@wri.com
• Distribution: local
• Newsgroups: wri.mathgroup
• Organization: Wolfram Research, Inc.
• Sender: daemon at wri.com ( )

```In article <44qj7k\$s22 at ralph.vnet.net>, Julian Charko
<jcharko at microage-ll.awinc.com> wrote:

> In order to plot the function f(x) = a^x, where a<0, over a
> range of integer values of x, what plotting options would you
> need to use with the Plot command?
>
> Specifying a plotting range of real numbers in the usual way,
> as shown below, for example, presents problems because
> Mathematica generates complex numbers for fractional exponents,
> and these obviously cannot be plotted by Plot.
>
>                  Plot[(-1)^x, {x, -5, 5}]

Well, you could either create a list of the function evaluated
for integer avlues of x and then use ListPlot to plot it, or
just plot the real part of your function. Both are illustrated
below.

In:=
pts = Table[{x,(-1)^x}, {x, -5, 5}]
Out=
{{-5, -1}, {-4, 1}, {-3, -1}, {-2, 1}, {-1, -1}, {0, 1},

{1, -1}, {2, 1}, {3, -1}, {4, 1}, {5, -1}}

In:=
ListPlot[ pts , PlotJoined -> True]

Out=
-Graphics-

In:=
Plot[Re[(-1)^x], {x, -5, 5}]

Out=
-Graphics-

I hope this helps.

--Ian

-----------------------------------------------------------
Ian Collier
Technical Sales Support
Wolfram Research, Inc.
-----------------------------------------------------------
tel:(217)-398-0700     fax:(217)-398-0747      ianc at wri.com