Math Forum / Math Software / Maple / February 2006

I've prepared a nice 3D diagram in the standard interface, using
transparency, and recently wanted to export it to a standard format, to
send to a collaborator.  When I right-click on the 3D-plot and select
"export..." and choose gif or jpg, I get very low quality files.  If I

Hi, this is probably pretty easy if
one knows how to do it:
I'd like to extract a diagonal Vector out of a Matrix
eg:

in order to finish my skilled work about cubical splines and polynomal
interpolation I have to know how I can plot about 25 functions, each in a
different interval.
Example:

     2                        1/2 1/2      1/2 1/2

I'm not getting the desired results using the following command to
compute a Hessian matrix:
with(VectorCalculus):
Hessian( 1/(x^2+y^2+z^2), [x,y,z] );

I thought I already posted, but everythings gone a bit squiffy, so I'll
try again and apologies if this appears twice...
I've got an error message looking like this:
Error, (in f) unable to store

     I'm trying to produce cobweb diagrams using Maple 9.  I have a
program I got off a web site that works for Maple 8 but not Maple 9.
Does anyone where I could get the information on how to update the
program?

I have got a set such as {x1=1,x2=2,x3=3,x4=4} ,
my question is how can I convert the set to two  arrays:
one is [x1,x2,x3,x4],and the other is [1,2,3,4], as well as
the variants x1=1;x2=2 ..and so on.

Thanks!

What is the best way in Maple to plot a sequence of discrete points?
Something similar to Matlab's "stem" function? Basically this is useful for  
plotting sequences in discrete-time/digital signal processing.
pointplot is almost the same except it doesn't have the "vertical line" ...

For example, how to rewrite this equation as a system of first-order
ODEs with Maple?
y'' - mu*(1 - y^2)*y' + y = 0
System of first-order ODEs:

I need to obtain numerically approximate expressions, in terms of two
parameters, for a few double integrals.  Most of these have no analytic
forms, so I use 'evalf' to evaluate them numerically.  For example, if x
and y are the two parameters, one of these double integrals boils ...

I am using Maple 9.
When I evaluate e.g.

I get the output

Dear Community
I want to solve the following system of equations with my Maple 7:
-- snip --
eq1:=N^2/2*eta1*QE1*eta2*QE2=12000;

How can I paste the graph produced by the Curve Fitting Assistant with
the data points marked as circles and the regression line in red onto a
document? or how can I recreate it outside of the Curve Fitting
Assistant?