Hi,

I have an issue calculating an electronics circuit with Maple, using units. I have a current source that I know, and I want to determin the voltage in a capacitor by solving an ODE (except that the current source is defined piecewise). And to make sure I have all the units and scales right, I use the standard unit package. All my variables have their units defined.

Except that Maple doesn't want to solve the equation. It seems to me that it assumes that the function I am trying to solve is unitless, and therefore refuses to solve. 

V__out := 3*Unit('kV');

C__out := 2*Unit('nF');
R__blead := 520*Unit('`kΩ`');

I__fly := proc (t) options operator, arrow; Unit('A')*piecewise(t < 3.25*Unit('us'), (1+(-1)*t/(3.25*Unit('us')))*.2, 0) end proc;

dsolve({I__fly(t*Unit('s'))-V__C(t*Unit('s'))/R__blead = C__out*(diff(V__C(t*Unit('s')), t)), V__C(0*Unit('s')) = V__out}, V__C(t*Unit('s')));
Error, (in Units:-Standard:-+) the units `A` and `S` have incompatible dimensions

Is there a way to make Maple assume the unit of what it's trying to solve ? I need it to understands that V__C is in Unit('V') ...

Thanks

Hi,

what i have to calculate in Maple for q=Mises-Stress and the third invariant of deviatoric stress as r???

It is for:

Link:
http://www.egr.msu.edu/software/abaqus/Documentation/docs/v6.7/books/stm/default.htm?startat=ch04s04ath116.html

Suppose we are given a matrix M[n*2n] of n linearly independent row vectors. Then I am trying to create a procedure to add n more linearly independent row vectors to this matix resulting in to a matrix M[2n*2n].

Consider this easy example, if the given matrix $M_{2*4}$ is

 
then we can add $[0,0,0,1]$ and $[0,0,1,0]$ to obtain the matrix $M_{4*4}$

Can I use rref form?Thank you for your help.

hi...amount of Determinant  is infinity?how i can remove this bad calculation ?

thanks...mode_shape2.mw

hi .by changing amount of variable such as '' f '' or 'D5 ' in input data, not changing  in final result!!!!please chek attached file 

thanksX4.mw

Hello,

I try his code:

for i to 6 do u[i, j] := (u[i-1, j]+u[i+1, j]+lambda*(u[i, j-1]+u[i, j+1])+sigma(h, r[i+1])*(u[i+1, j]-u[i-1, j]))/mu end do;

 
Error, too many levels of recursion.

I want to the  results of the analytic equations, for example:

                                                          
 u[1,j]= (u[0, j] + u[2, j] + lambda (u[1, j - 1] + u[1, j + 1])                                                       

      + sigma(h, r[2]) (u[2, j] - u[0, j]))/mu

.

.

.

.
Regards.

Suppose that we have the following curve on a unit sphere

r^2+z^2=1

phi=pi/3

-1<=z<=1

which is the implicit equation of a circle in "cylindrical coorinates" (r,phi,z) on the sphere.

How can I plot this curve without solving the implicit equation for r or z ?

Also, I don't want to make any parameterization.

See attached file and code

0. This is the differential equation I'm trying to do:

http://www.intmath.com/differential-equations/6-rc-circuits.php

https://i.imgur.com/zlVIisR.png

1. After you look at the above imgur link, could you help me with this error 

Error, (in Units:-Standard:-+) the units ``&Omega;`` and `1/F` have incompatible dimensions

2. Why does my solve ODE fail? 

See my code: 

test_maple.mw

Spiral on the cone. 







Yes, of course, in Maple.  The same source

I have Maple package "DESOLVE" having two different types of files namely in format .mpl and .mws, where code is written in .mpl file and .mws is just a example worksheet, this package is available at following link;

http://cpc.cs.qub.ac.uk/summaries/ADYZ_v1_0.html

My problem is how to work with package?

One thing that I able to do is that I have opened the file type .mpl  in Maple worksheet and after executing whole whorsheet I able to to start working with package using with(desolv).

But when I type with(desolv) in new worksheet an error shows up.

How I can store this .mpl file in Maple library so as to use this package using "with(desolv)" in new worksheets

Desolv_worksheet_paper.mws?

Hello,

Remark by Markiyan Hirnyk:

The part of the body of this question disappears after my edit of its title only.

I want to have a matrix such that 

Crosslinking surfaces by a spiral.



My fantasy is a source.

eq1 := z = y*log(x): eq2 := z = y+x*log(x):

DispIntersecting := implicitplot3d([eq1, eq2], x = 0 .. 10, y = -30 .. 30, z = -40 .. 40, color = [blue, green]):

solve({eq1, eq2}, [x, y, z]);

assign(%):

DispIntersection := spacecurve([x, y, z], x = 0.1e-2 .. 10, color = red, view = [0 .. 10, -30 .. 30, -40 .. 40]):

display(DispIntersecting, DispIntersection, axes = boxed, scaling = constrained);

This is really weird.

restart;
eq:=phi(f(x,y(x),diff(y(x),x)),g(x,y(x),diff(y(x),x)));

Does any one see a "||" in the above? I do not. Then why Maple shows this:

r := cat("dsolve(",eq,",y(x))");

       r:="dsolve("||phi(f(x,y(x),y'(x)),g(x,y(x),y'(x)))||",y(x))"

This is Maple 2015 on windows. Running in worksheet mode

Here is screen shot

This problem does not show up all the time. For example, this works ok:

No "||" added. The problem with all the above, is that I can't make it all as a string in the first example above. I am trying to make a string of   "dsolve(" + ode + "),y(x)"

Here is the display options

thank you