Compare the results of isdifferentiable on 3 piecewise defined expressions f, g, and h.

The first time the order of the asking is f, g, h. The second time (after a restart) the order is h,g,f.

The results are remarkably different! What is going on?

isdifferentiable was first brought to my attention within the last week or so, maybe it is not reliable?

If you remove all the lines with 'assuming' then the inconsistency remains.

restart;

If you make a misspelling in spacecurve as in

plots:-spacecurve([ARctan(t),t,t], t=0..10);

then Maple 13.02 (Standard) loses contact with the kernel.

Even if you forget 't ='  as in

plots:-spacecurve([ARctan(t),t,t],0..10);

Maple will lose contact.

It seems that also Maple 12 has a problem.

Maple 13 Classic doesn't have the problem.

Will these and other 3d-plot problems be corrected in Maple 14?

Preben Alsholm