Julien,
you can use an if-then-else construct to define your function.
A function definition is done by := and Eulers number is %e
(%i1) f(x):= if x<=0 then (%e^x)/3 else 1$
(%i2) plot2d(f(x),[x,-2,2],[y,0,1.1])$
The plot shows a vertical connection between the parts. If you don't want to see this, define
the two parts separately. In each I leave one part undefined, which remains unplotted.
(%i3) f1(x):= if x<=0 then (%e^x)/3$
(%i4) f2(x):= if x>0 then 1$
(%i5) plot2d([f1(x),f2(x)], [x,-2,2], [y,0,1.1])$
And make usage of some plot options to get a more advanced plot. E.g.
(%i6) plot2d([f1(x),f2(x)], [x,-2,2], [y,0,1.1], [gnuplot_preamble,"set grid;"])$
HTH
Volker van Nek
Am 11 May 2008 um 10:40 hat Julien Martin geschrieben:
>
> Hello,
>
> I have a function defined as follows:
>
> F(x)=(e^x)/3 for x<=0
> F(x)=1 for x>0
>
> I need to plot this function. How do I do that bearing in mind that the function definition changes
> according to the values of x???
>
> Can anyone please help?
>
> Thanks in advance,
>
> Julien.