I have the following equation:

Diff(W(t), t) = -q*V*(sin(Phi)-sin(Psi[s]))/(2*h*Pi);

I solve it for rhs() = 0:

soln := solve([rhs((2)) = 0, Phi < 2*Pi], [Phi], allsolutions = true,explicit);

This works and I get this result:

Now I want to get the first zeros, which occur for _Z1 and _Z2 equal to 0. So I substitute:

subs(_Z2=0,(3));

and get

In other words, the substitution did not work.

The original problem is embedded in a larger sheet created with Maple 15 and there it does work. It fails on Maple 2015.2. I then pulled out the relevant pieces to make this example demonstrating the problem (see the attached sheet, which has some of my other (unsuccessful) attempts to diagnose what is going on). It seems like the created variables _Z1 and _Z2 are somehow not recognized at all.

The only way I can get the _Z2 terms out is to substitute 2=0. This is really too icky to seriously consider, though.

Anyone has seen this before?

FWIW: Maple 2015.2 on Mac OS X 10.10.5.

Thanks,

Mac Dude

Assumptions_test.mw

This is not actually a question, but an interesting problem found in the recent book (2nd edition, 2015):
Mathematica®: A Problem-Centered Approach
by  Hazrat Roozbeh
Springer

I hope that you will enjoy the problem too.

Define the functions f, h : N --> N by
f(n) = the sum of the squares of the digits of n; e.g. f(25) = 2^2 + 5^2 = 29.
h(n) = min {f(n), f(f(n)), f(f(f(n))), ... };  e.g. h(7)  = min{49,97,130,10,1} = 1.

A natural number n is happy if h(n) = 1.
Find all the happy ages, i.e., happy numbers up to 100.
Conclude that happy ages are mostly before one gets a job or after retirement!

Hello,

I would like to plot coupled elliptic parametric curves.

I have a problem in the for loop in my code. The index i of the phi variable is not incremented.

Here my code:

for i to 4
do
u[i]:=t->L/2*cos(w*t);
v[i]:=t->H*sin(w*t+phi[i]);
end do;

The result looks like this :

u[1](t) -> - L cos(w t)
v[1](t) -> H sin(w t + phi[i])

u[2](t) -> - L cos(w t)
v[2](t) -> H sin(w t + phi[i])

u[3](t) -> - L cos(w t)
u[3](t) -> H sin(w t + phi[i])

u[4](t)  -> - L cos(w t)
u[4](t)  -> H sin(w t + phi[i])

And i would have prefered :

u[1](t) -> - L cos(w t)
v[1](t) -> H sin(w t + phi[1])

u[2](t) -> - L cos(w t)
v[2](t) -> H sin(w t + phi[2])

u[3](t) -> - L cos(w t)
v[3](t) -> H sin(w t + phi[3])

u[4](t)  -> - L cos(w t)
v[4](t)  -> H sin(w t + phi[4])

Do you have ideas how I can obtain iteration on my phi variable ?

Thank you for your help.

Can some one help me " How to conert a three or four coupled equation by using non dimensions variable "

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('`k&Omega;`');

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.