Problem description and solution can be found at http://www.maplesoft.com/support/faqs/detail.aspx?sid=98818

Yes, combining plots can be done by plots[display](plot1,plot2);

Note that you have to assign the plots using the correct operator which consists of colon and equal:

plot1:=odeplot(...):

plot2:=odeplot(...):

When you load the plots package anyways (for odeplot), you can write display(...) instead of the long form plots[display](...).

Patches are available at http://www.maplesoft.com/support/downloads/index.aspx, but they don't help with Windows 7. Maple 9 appeared in 2003 and is not compatible with Windows 7. The current version Maple 14 is, of course.

You can also enter solve(x^2=4,x,useassumptions) assuming x>0;

which is documented under ?solve,details.

Not really an elegant approach, but you could construct the date explicitly by using

with(StringTools):
ft:=FormatTime("%Y-%m-%d");
pt:=ParseTime("%Y-%m-%d",ft);
nt:=cat(convert(pt:-year,string),"-",convert(pt:-month-1,string),"-",convert(pt:-monthDay,string));

The special case of January is left as an exercise to the reader. ;-)

This can be achieved through the parse command; see ?parse in the help system.

These error messages can have several reasons. A firewall (or some other security related software) may be blocking communication between mserver (the Maple kernel) and the user interface. Or the license file may be missing or inaccessible. If you are using a network license, the VPN connection to your university may be down. And so on.

I suggest that you send me an e-mail at trichard@maplesoft.com. In case of a single user installation, please include your Purchase Code so that I can look up your license file in our database. The OS X version number might also be relevant, as well as the Maple install log file.

Edit: I forgot to mention that you can write the e-mail in German.

There is definitely no such command in Maple, but a web search for lfsrlength turns up things like http://www-users.math.umd.edu/~lcw/MatlabCode/lfsrlength.m

And that can easily be translated to Maple (modulo interpretation mistakes, as I don't have MATLAB):

n:=15:
V:=Vector([1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1]);
p:=2:
with(LinearAlgebra[Modular]):
for j from 1 to n do lprint(j,Determinant(p,Matrix(j,shape=Circulant[V]))) end do;

Use print instead of lprint if you prefer. This is for interactive experiments anyways. If you need to turn this into a proc, be sure to use avoid the "with" call.

Just supply the package name, correct a typo, use double quotes, and concatenate the parts:

currentdir(kernelopts(homedir)): # can't write to C:/ directly
test:=[1,2,3,4,5,6]:
filename:=cat("data-",StringTools:-FormatTime("%B%d%H%M"),".txt");
writedata(filename,test);

If you open the ?Maplets,Elements,Plotter help page, the third example should give you an idea on how to make this work. To use two animations in the same Plotter, adjust it like

p1 := plots[animate](plot,[a*x+2*a,x=-10..10],a=-5..5,frames=20):
p2 := plots[animate](plot,[a*x-2*a,x=-10..10],a=-5..5,frames=20):
p:=plots[display](p1,p2):

and the rest can be left unchanged, at least for initial experiments.
 

I can't speak for "other 3d-plot problems", but this particular one has recently been reported by another user. So chances are good to see a fix in the next release.

Please upload an mw file instead. Chances are better that someone will run this (as opposed to typing in the contents of a PDF file).

There are various possibilities; the best is probably inserting a so-called interdocument reference via Insert > Reference. Please see the documentation at ?interdocumentreference. This feature was introduced in Maple 11.

If you are living in Germany or Austria (as your name suggests), you can send us your nb file (including the DSolve call), and we'll see if Maple finds a better result. Please contact us at  maple.support@scientific.de and provide some details (customer group etc.).

This is due to a change in Maple's usage of OpenGL: Maple 13 tries to access hardware-accelerated features and usually requires current graphics drivers. Most solutions are collected in this FAQ.

The only Solaris specific hint is disabling that feature through USE_SOFTWARE_GL=1. Does that help for your systems?

If not, we'll probably need more configuration details (hardware, software versions etc.).

[Edit: updated FAQ link and removed obsolete support link.]