problems with maxima 5.22.1

Hello Maxima-team

I'd like to report a bug in Maxima 5.22.1

I'm using a tutorial from Mr Edwin L. Woollett : Maxima by Example : 
(http://www.csulb.edu/~woollett/)

In chapter 6 he explains vector calculus and he provides some batch 
files to convert from coordinate systems (cartesian, cylindrical, spherical)

see :

http://www.csulb.edu/~woollett/mbe6calc1.pdf
http://www.csulb.edu/~woollett/cylinder.mac
http://www.csulb.edu/~woollett/sphere.mac

The batch files "cylinder.mac" and "sphere.mac" don't work correctly in 
Maxima 5.22.1. (under Linux 64-bit Debian Sid and Windows Vista 32-bit)
The curl, divergence and laplacian are not calculated correctly.

With maxima 5.20.1 it works perfectly (Windows Vista 32-bit) and the 
results compare with the data in "mbe6calc1.pdf."

Attached you have the printouts of the "cylinder.mac" batch file for 
both versions.

For the laplacian the error is in the calculation of diff(f,x,2) (see 
line %82), which returns a zero. For the divergence and the curl I 
haven't found the error yet.

Hope this information allows you to correct the bug.

If you need more information please don't hesitate to contact me.

Anyway thanks for the excellent tool you are providing !

Best regards,

Bruno Torremans
Bousval - Belgium
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