I've seen something like this happen when a file becomes corrupted after saving, and then when re-opened, everything is garbled at the top.

But I've never seen it happen "all of a sudden" while just performing some random task in the worksheet/document.

Is there any pattern for when this happens to your students ? Are they doing anything in particular when it happens ? Is this on their own PCs/laptops or with institution hardware ? If the latter, does it only happen on certain machines and/or with certain students' documents/worksheets ?

FWIW, on the courses I have taken, we were always encouraged to use classic mode worksheets, in order to avoid possible problems with "pretty" input/output so we could focus on just the mathematical Maple programming aspects.

Isn't this a bit more straightforward ?

axsym:=proc(f::mathfunc)

solve(D(f)(x)=0);

end proc:

Obviously this assumes that the input is a function, not an expression, and it's a quadratic, and the independent variable is x.

If the input is an expression, not a function, then this should work

axsym:=proc(f)

solve(diff(f,x)=0,x);

end proc;

I have seen something similar happen with other applications, and it has turned out to be a keyboard mapping problem, though the freezing problem seems very odd. Are you able to quit Maple using the mouse, after it freezes ? Does it give any error ?

Which mode are you working in when this happens - did you create and new "document" or "worksheet" ? Does the problem manifest with both ?

Also, are you able to open a worksheet or document such as one that came with Maple, or that you downloaded from maplesoft.com and run them with no apparent error ?

Hi Robert, thank you for that.
This is probably asking too much but is there any way to persuade Maple to express the result without using cosh and sinh ? I've verified that the solution is the same as the one obtained by hand for the range of values I'm interested in, but I'd like to have Maple produce it in a similar form if possible.
LR

Hi Alex, and thanks again.
It's frustrating that I can't check it easily with Maple. Is this normal for PDEs ? I can only get a trivial solution for this, even simpler, one too, without any initial conditions:
PDE:=diff(u(x,y),x$2)+diff(u(x,y),y$2)+u(x,y)=0;
BCs:=u(0,y)=0,u(1,y)=0,u(x,0)=0,u(x,1)=0:
ans := pdsolve([PDE,BCs],u(x,y));
ans := u(x, y) = 0

Thanks Alec ?
Have I specified the ICs incorrectly ? I am trying to achieve the same result as that done by hand in the attachments.

I found this very helpful
http://www.mapleprimes.com/book/frontend

I replied to you in a different thread but I see you provided more details here. Does this happen every time you use any of those commands ? Or just with certain parameters ? Does it happen after a reboot ? I had similar problems with lost kernel connection, though never with those commands. I found it was caused by problems in my code, but it wasn't always predictable. I submitted a bug report.

Like Patrick, I use ccleaner. It'f free and has served me well for years. Just google it.

I get the same as Doug. What is the expression you are clicking on ? Have you tried with others ?

I can't see the links above, you seem to be linking them to your own computer
http://c/DOCUME~1/Joshu/LOCALS~1/Temp/moz-screenshot-5.png
I think you need to upload the files to mapleprimes first
Anyway, check this
http://www.maplesoft.com/support/help/AddOns/view.aspx?path=worksheet/interactive/plot
That shows what I think you *should* get !

Use the bincount parameter to increase the number of bars. eg
Statistics[Histogram](A,bincount=20);
And there are other options. Check ?Histogram.
Note there is also a ImageTools[Histogram] so make sure you look at the right page !

I've replied on the course forum also. The problem may be that you have 64 bit windows, possibly the installer doesn't run properly (evidently the uninstaller doesn't either !) . The only good news (of sorts) I can give you is that if you decide to buy Maple 13 (around 80pounds with instant download from maplesoft) that should solve the problem. I also have 64 bit win 7 and it works for me (haven't tried Maple 11). It's a serious investment, but then it gives you the incentive to really make the most of it.
Otherwise, it would be good if we can actually get clarifaction of whether Maple 11 will or will not work with Windows 7 Home Premium. If not then there's no much point trying other ideas. If it will, then I guess your problem is just with the activation code supplied by the course (I know there have been problems with this).
Can anyone advise: Will Maple 11 work on 64 bit Win 7 Home Premium ?

Right-click an expression and select Plot Builder from the Plot menu. in the resulting dialog box click Options. The next dialog box will have "Find Discontinuities" check box on the right hand side.

As you'll know from the course forum, other students have got it to work with win7 enterprise and win7 home. To check your version of windows, go to Control Panel->System here can see what edition you have (home, professional, enterprise, ultimate etc) and also what system (32 or 64 bit) you have. Hope you don't mind, but I'll post your follow up message to the course forum here, in case anyone here has further advice:
"I have tried renaming the files in the license folder and I have tried to uninstall and to activate licence key both failed. I have a Maple 11 install log on my desktop now saying thaat I have successfully installed twice(I think thats what it says anyway) I even tried a system restore to before the second time I tried to install it (the first time the uninstaller worked but i still had the old out of date product key) I am scared to system restore going further back as I installed Microsoft office after I installed Maple and I am afraid they will charge me again if I system restore and lose everything if you catch my drift. thanks for the suggestions though."
So what is the current status ?