       Mathematica conundrum

• To: mathgroup at christensen.cybernetics.net
• Subject: [mg1782] Mathematica conundrum
• From: Zorro <berriz at husc.harvard.edu>
• Date: Sun, 30 Jul 1995 21:35:46 -0400
• Organization: Harvard University, Cambridge, Massachusetts

```Hi.  When I issue the command

Plot[Exp[-5x],{x, 0, 5}, PlotRange->{0,1}];

Mathematica produces the plot without a hitch.  Similarly, when I
issue

Plot[Exp[-x],{x, 0, 5}];

Likewise, the command

Plot[Evaluate[Table[Sin[n x],{n, 5}]],
{x, 0, 1}, PlotRange->{-1, 1}];

produces, as expected, a series of superimposed sine waves.  BUT,
Mathematica balks at

Plot[Evaluate[Table[Exp[-nx],{n, 5}]],
{x, 0, 5}, PlotRange->{0, 1}];

spitting out

Plot::plnr:
CompiledFunction[{x}, <<1>>, -C<<11>>-][x]
is not a machine-size real number at x = 0..
Plot::plnr:
CompiledFunction[{x}, <<1>>, -C<<11>>-][x]
is not a machine-size real number at x = 0.208333.
Plot::plnr:
CompiledFunction[{x}, <<1>>, -C<<11>>-][x]
is not a machine-size real number at x = 0.416667.
General::stop:
Further output of Plot::plnr
will be suppressed during this calculation.

... and an empty plot (two axes, no graphs).

Why is this?  What could the error messages mean??  After all,
Exp[-nx] is well-behaved everywhere, and reasonably valued in the
requested ranges of x and n.  ( I have no problems when I try to
produce the plots individually (for each value of n), nor when I use
Show to combine them in a single plot...)

And the meta-follow up: is there a reference I could have looked up
(besides possibly reading Wolfram's book cover-to-cover) to find the