Problem with parametric plot



On Thu, 2007-04-05 at 08:25 +1000, Alasdair McAndrew wrote:
> You can use any variable you like as your parameter, as long as you
> use the gnuplot "set dummy" command.  But I was initially wrong: you
> do need to pass functions to plot 2d; for example:
> 
> (%i1) x(s):=cos(s);
> (%i2) y(s):=sin(3*s);
> (%i3) plot2d([parametric,x(s),y(s),[s,0,2*%pi]],[gnuplot_preamble,"set
> dummy s"],[nticks,180]); 
Thanks for pointing that out.
It actually works, both in gnuplot and openmath, without setting any
dummy variables and without defining any functions:
   (%i4) plot2d([parametric,x(s),y(s),[s,0,2*%pi]],[nticks,180]);
or
   (%i5) plot2d([parametric,cos(s),sin(3*s),[s,0,2*%pi]],[nticks,180]);

I must be getting senile :) I wrote the section on parametric plots in
the manual last weekend, and I replaced myself the [t,max,min] in the
old version by [param,mix,max] precisely because the parameter does not
have to be t anymore.  

Regards,
Jaime