Something goes wrong with the DE   : de  
Error, unexpected single forward quote

I solved this by converting this : de  to a 2 D Math input 
Something must be chanced
in the configuration settings ? 

Ch05Sec03Prob19.mw

Area of shadow : i have studied one way of solution by hand, but now in Maple ?
Note: for math illustrations : geogebra seems to be wel suited

I know for ordinairy differential equations (ODE) there is a odeadvisor in Maple what shows information about the equation .

What is is possible with a partial differential equations (PDE) package.
Is there a help like for ODE's ?

How to install this old package for Maple 6 , should be trivial but turns te be out a puzzle with no result so far.

### This is the Maple initialization file created for use with the 
### LAMP modules. For Maple 6 in Windows 95, 98, 2000, or NT, this file 
### should be installed in the folder 
###
###        C:\Program Files\Maple 6\BIN.WNT
###
### The last three letters, WNT, may vary with the version of Windows.
###
### The following lines set up libname, so Maple knows to look in the
### proper folder to find the Lamp library. If you did not put the 
### Lamplib folder in C:\lamp6\lamplib, you must edit the first line.

lamppath := "C:\\lamp6\\lamplib\\":
libname := `lamppath`, libname:

### The following line enables one to use the command read(lampstart) 
### to establish the Lamp environment. It is optional.

lampstart := cat(lamppath,"lamp.txt"):

I am going now into 3D with the conics 
Ax^2+BY^2 +Cz^2 +Dxy'..........................................(general formula quadric surfaces)

Is there a existing procedure in Maple for this. 
Perhaps also with different coordinate systems ?
Probably is this too much asked.

I followed the post about two intersected cilinders.