I am trying to write a procedure that uses LinearAlgebra[SingularValues].
For some reason, the line
U,S,Vt := LinearAlgebra[SingularValues](covariance, output=['U','S','Vt']);
causes the procedure to give the error message:
Error, (in LinearAlgebra:-LA_Main:-SingularValues) invalid output (U) specified
However, outside the procedure the same line works perfectly.
Any help will be much appreciated!

Hi,
I was wondering if there is a way to use Document Components or Maplet Elements from Java?
Is there a file that has the library for these components?
I use the Netbeans environment, has anyone set up that environment to use Maple libraries?
Thanks,
Art

I incidently put in an incorrect item response. The deadline has been passed and now I would like to correct the students scores. Is there a way to redo the evaluation of an existing data-base in Maple TA 2.5?
Harry Garst

Is there a way to export the item responses to a tab-delimited file in Maple TA 2.5? I would like to analyse the item responses and so far there seems no possibility to transfer the item responses. Only grades can be exported. I hope I am wrong, because it is difficult to understand what the reason is to prevent exporting the responses?
Harry Garst

I have the initial and boundary conditions:
cond := ro(x, 0) = 0, v(x, 0) = 0, {ro(0, t) = 10, ro(40, t) = 20}, {v(0, t) = 10, v(40, t) = 20};
The PDE system is:
sys2 := {diff(ro(x, t), t)+diff(ro(x, t)*v(x, t), x) = 0, diff(v(x, t), t)+v(x, t)*(diff(v(x, t), x))+3*ro(x, t)*(diff(ro(x, t), x)) = 0};
I use:
sol1 := pdsolve(sys2, {cond}, numeric, time = t, range = 0 .. 40);
values := sol1:-value();
...
When I try to see the values I receive the following error:
values(40, 20);
Error, (in solnproc) unable to compute solution for t>0.:
column vector dimension less than length of sparse data

I am trying to calculate the second derivative of a taylor expansion. Could anyone tell me how to enter this command?
Thanks
Rachel

Can someone point me in the direction to integrate a maple file into a java program?
I made a maple file that has a variable and will output a final graph after long calculations..
What I want is a nice java app where the user can simply type in the variable they want, and a graph is displayed in a window?
Just a general kick in the butt to the direction for documentation about such a process would be great!
Thanks!

Hello,
I'am using Maple 11 and have the following problem concerning plots of ODE:
ode := M*(diff(x(t), t, t))+K*x(t) = Force;
sol := dsolve({ode, x(0) = 0, (D(x))(0) = 0}, numeric);
xx := (t) -> rhs(sol(t)[2]);
dx := (t) -> rhs(sol(t)[3]);
M := 1;
K := 4*Pi^2;
test := proc (F, t)
global Force;
Force := F;
xx(t)
end proc;
When I call test(F,t) directly everything works fine:
test(2, 2);
-2.49946953367608378 10 .....
However, when I try to plot the test-function vs Force I get an error message:
plot(test(pressure, 1), pressure = 1 .. 3);
Error, (in sol) global 'Force' must be assigned to a numeric value before obtaining a solution

I've been trying to plot the function
f:=x->(e^(-a*x^2)-b*x*ln(1+x^2))/(2+x^2+c*sin(Pi*x));
with values a,b,c which have been assigned on maple. when i try to plot the function using:
plot(f(x),x=-4..4);
I get the error:
Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct
Error, empty plot
I have tried all ways i can possibly think and cannot get it to plot the graph. Can anyone help?

Although this question might seem silly to Maple experts, I cannot help asking, since despite a long search through Maple Help and Maple Guides I was not able to come across the answer. What I mean is this:
```
> eq1 := diff(y(t),t)-y(t)^2+y(t)*sin(t)-cos(t) = 0;
> # here I want some command that would return the order of eq1, i.e. 1
> something(eq1);
```

```
> eq2 := diff(y(t),`$`(t,2)) = y(t)*u(t) + diff(u(t),t);
> something(eq2,y); # this should return 2
> something(eq2,u); # this should return 1
```

Besides, I would also need the same for recurrent (shift) equations, i.e.

Marben packaging makes open boxes(no Top) out of cardboard squares whose sides are 6 ft. long. What is the maximum volume they can obtain from the cardboard

Defferentiables
Two highways intersect at right angles. Car A on one highway is 0.5 kilometer from the intersection and is moving toward it at 96 kilometers per hour, while car B on the other highway is 1 kilometer from the intersection and is moving away from it at 88 kilometers per hour. At what rate is the distance between the two cars changing at the instant.

I got an interesting error message

assume(x>0);
assume(lambda>=0);
f:=(x,lambda)->2/(1+lambda)*1/( 1/(x+lambda)+1/(1+lambda));
2
(x, lambda) -> --------------------------------------
/ 1 1 \
(1 + lambda) |---------- + ----------|
\x + lambda 1 + lambda/
ftilde:=(x,lambda)->1/2*(x+1-(x-1)^2*f(0,lambda)/f(x,lambda));
2
1 1 (x - 1) f(0, lambda)
(x, lambda) -> - x + - - ---------------------

Hi,
I'm trying to solve a set of simultaneous equations, and the solutions I get are expressions of _Z. I'd be most grateful if anyone could explain what this means.

Hi,
I stored the closed-form symbolic result of a long computation in a library.
When I try to substitute numerical values into the functions I saved, subs (applyrule, etc.) do not make the substitution.
Looking at the operand that I think should substitute ('Ip' as stored), it is not evalb equal to 'Ip' (as typed into evalb).
It appears that Maple thinks I have two different symbols with the same name.
Can anyone explain this behavior to me?
Thanks,
Art