Re: What am I doing wrong with this code?
- To: mathgroup at smc.vnet.net
- Subject: [mg82545] Re: [mg82519] What am I doing wrong with this code?
- From: DrMajorBob <drmajorbob at bigfoot.com>
- Date: Wed, 24 Oct 2007 04:28:19 -0400 (EDT)
- References: <14846561.1193151252112.JavaMail.root@m35>
- Reply-to: drmajorbob at bigfoot.com
It plots just fine at this machine (WinXP, Mathematica 6.0.1).
IIRC, v5.2 would complain about complex numbers arising from the second
function for y > 1. If that's the problem, you can split it in two plots
and Show the results, something like this:
Show[Plot[1/(1 + y^2), {y, 0, 5}], Plot[Sqrt[-1 + 1/y], {y, 0, 1}]]
or perhaps
Clear[f]
f[y_] /; y <= 1 := Sqrt[-1 + 1/y]
f[y_] = 0;
Plot[{1/(1 + y^2), f@y}, {y, 0, 5}]
Bobby
On Tue, 23 Oct 2007 04:32:30 -0500, sean_incali <sean_incali at yahoo.com>
wrote:
> I think I'm having a brain fart. Seriously...
>
> Plot[{1/(1 + y^2), (1/y - 1)^(1/2)}, {y, 0, 5}]
>
> What is wrong with that code? Maybe it's not solvable in mathematica?
>
> I'm trying to plot nullclines of a system of ODEs. and those function
> up there are them. I just can't get mathematica to plot them in the
> same graph.
>
> I get an error message saying...
>
>> From In[22]:=
> (1/y - 1)^(1/2) is not a machine-size real number at y =
> 1.0000001666666667`.
>
> Any help is appreciated.
>
> sean
>
>
>
--
DrMajorBob at bigfoot.com