Re: Plotting

*To*: mathgroup at smc.vnet.net*Subject*: [mg2163] Re: Plotting*From*: ianc (Ian Collier)*Date*: Wed, 11 Oct 1995 01:58:20 -0400*Organization*: Wolfram Research, Inc.

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[6]:= pts = Table[{x,(-1)^x}, {x, -5, 5}] Out[6]= {{-5, -1}, {-4, 1}, {-3, -1}, {-2, 1}, {-1, -1}, {0, 1}, {1, -1}, {2, 1}, {3, -1}, {4, 1}, {5, -1}} In[7]:= ListPlot[ pts , PlotJoined -> True] Out[7]= -Graphics- In[8]:= Plot[Re[(-1)^x], {x, -5, 5}] Out[8]= -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 Wolfram Research Home Page: http://www.wri.com/ -----------------------------------------------------------