I beg to differ...
lemire@lagrange lemire]$ maxima
GCL (GNU Common Lisp) Version(2.5.0) ven fév 15 14:16:05 AST 2002
Licensed under GNU Library General Public License
Contains Enhancements by W. Schelter
Maxima 5.9.0pre-cvs (with enhancements by W. Schelter).
Licensed under the GNU Public License (see file COPYING)
(C1) limit(tan(x),x,%pi/2,plus);
(D1) MINF
(C2)
> >>>>> "Daniel" == Daniel Lemire <daniel.lemire@acadiau.ca> writes:
>
> Daniel> (C1) limit(tan(x),x,%PI/2,MINUS);
> Daniel> (D1) INF
> Daniel> (C2) limit(tan(x),x,%PI/2,PLUS);
>
> Daniel> (D2) MINF
>
> You really need to quote the MINUS and PLUS:
>
> (C1) plus:18;
>
> (D1) 18
> (C2) limit(tan(x),x,%pi/2,plus);
>
> Fourth argument must be either PLUS or MINUS - LIMIT
> -- an error. Quitting. To debug this try DEBUGMODE(TRUE);)
> (C3) limit(tan(x),x,%pi/2,'plus);
>
> (D3) MINF
>
> Ray