I have the problem that I'm unable to insert constant functions into a plot. Maxima will do calculations forever and hangs (using CPU power).
I found out that _some_ constant functions are indeed plotted but only those that have the form 2^z.
So for example you can plot y=0.5, y=1, y=2 or y=0.03125. Things don't work are y=0.4 or y=0.028
This is in all revisions I tested so far including the recent 5.10.