## Can I solve this Inverse Laplace?...

Hello,

I tried to solve below equation, but it gives me zeros result. Please help me to find their inverse laplace.

It will be clearer if was pasted on Maple:

restart

Ps := [P[0], P[1], P[2], P[3], P[4]]:

eqs := [P[0](s) =~ (P[1](s)*mu[1]+P[2](s)*mu[2]+P[3](s)*mu[3]+P[4](s)*mu[4])/(s+lambda[1]+lambda[2]+lambda[3]+lambda[4]), P[1](s) = lambda[1]*P[0](s)/(s+mu[1]), P[2](s) = lambda[2]*P[0](s)/(s+mu[2]), P[3](s) = lambda[3]*P[0](s)/(s+mu[3]), P[4](s) = lambda[4]*P[0](s)/(s+mu[4])];

Ls := solve(eqs, Ps(s))[];

P(t)=~inttrans[invlaplace]~(rhs~(Ls), s, t);

Thank you

## Show calculations step by step...

How do I make maple to show the values of my variables in my calculation automatically? I want it to look somewhat like this:

https://gyazo.com/df9fe1193091fb771ff99d6187c9195f

https://gyazo.com/936894920a6cb89082fb94d66f8e4291

## How to find invlaplace?...

Hello

I have a complex set of Markov Processes in reliability application. To make them simpler for me, as a beginner in Maplesoft, I solve them manually to reach a point where I need inverse Laplace for a set of equations. For illustration, I used a simple example below. If I get the concepts for below example, I can apply them on more complicated systems, as following:

P0(s) = 1/(s+λ)+υ*P1(s)/(s+λ)

P1(s)=γ*P0(s)/(s+υ)

Mannuly I find that:

P0(t)=υ/(s+λ)+λ*exp(-(λ+υ)t)/(υ+λ)

P1(t)=υ/(s+λ)-λ*exp(-(λ+υ)t)/(υ+λ)

Thank you,

## Tough BesselJ Integral...

Hi,

I have a list of 603 integrals that I want to evaluate. Unfortunately, I can't get Maple to do most of them. Mathematica can do some that Maple can't, and returns an answer in terms of BesselJ functions. So my question is 2-fold

1) Is there a way to make Maple do this integral?
2) If not, is there a way to efficiently convert 603 expessions to Mathematica and back?

EXAMPLE INTEGRAL
restart;
assume(k1::real, k2::real, R::real, R>0);
a :=cos(x)*exp(I*(k1*R*sin(x)+k2*R*sin(x)-4*x))*sin(x):
int(a, x=-Pi/2..Pi/2) assuming real;

Thanks!

 > restart;
 > assume(k1::real, k2::real, R::real, R>0);
 > a :=cos(x)*exp(I*(k1*R*sin(x)+k2*R*sin(x)-4*x))*sin(x)
 (1)
 > int(a, x=-Pi/2..Pi/2) assuming real;
 (2)

 > ans := -(1/((k1 + k2)^6*R^6))*2*I*Pi* ( 10*(k1 + k2)^4*Pi*R^4*BesselJ(2, sqrt((k1 + k2)^2*R^2)) + 2*Pi ((k1 + k2)^2*R^2)^(3/2) (-30 + (k1 + k2)^2*R^2) *BesselJ(3, sqrt((k1 + k2)^2*R^2)) - (k1 + k2)^4*R^4*(-(k1 + k2)*R*cos((k1 + k2)*R) + sin((k1 + k2)*R)) + 8*(k1 + k2)^2*R^2*(-(k1 + k2)*R*(-6 + (k1 + k2)^2*R^2)*cos((k1 + k2)*R) + 3*(-2 + (k1 + k2)^2*R^2)*sin((k1 + k2)*R)) - 8*(-(k1 + k2)*R*( 120 - 20*k2^2*R^2 + k1^4*R^4 + 4*k1^3*k2*R^4 +
 > k2^4*R^4 + 4*k1*k2*R^2*(-10 + k2^2*R^2) +
 > k1^2*(-20*R^2 + 6*k2^2*R^4))*cos((k1 + k2)*R) +
 > 5*(24 - 12*k2^2*R^2 + k1^4*R^4 + 4*k1^3*k2*R^4 + k2^4*R^4 +
 > 4*k1*k2*R^2*(-6 + k2^2*R^2) +
 > 6*k1^2*R^2*(-2 + k2^2*R^2))*sin((k1 + k2)*R) ) );
 (3)
 >
 >

## Too many levels of recursion...

Hello,
I have defined a function f (x, e, y).  I give values of n: = i * h as follows:

f (x (n), w (n), t) = w * t * x;
n: = i * h;
r (n) = n;
Then I need to do this operation:
w (n) = w (n) + r (n);

w(n):=15; r(n):=30;

w(n):=w(n)+r(n);

w(n);
Error, (in w) too many levels of recursion.

How i can operate?.

Regards.

## Division of estate...

Wonder if this can be accomplished in Maple.

so I have a list of 100 items labeled {1..100} of various value {\$100, \$160, \$220, ......  , }

the task is to distribute these items among 3 people A,B,C so they get an approximately equal share.

Adding the values and dividing by 3 gives the dollar total to aim for.

This post has C.Love procedure for evenly sized groups

http://www.mapleprimes.com/questions/200480-Product-Grouping

but what i want is a method for different sized groups. ie 25 items for A, 35 for B and 40 for C (user defined).

additionally there is a fixed constraint: A has been bequeathed items 1,4,8; B items 2 and 20; C item 50.

restart:
S:= {3, 4, 5, 6, 8, 9, 28, 30, 35}:
SL:= [A,B,C,D,E,F,G,H,I]:
assign(Labels ~ (S) =~ SL); #Create remember table.
AllP:= [seq(P, P= Iterator:-SetPartitions(S, [[3,3]], compile= false))]:
lnp:= evalf(ln((`*`(S[]))^(1/3))):

Var:= proc(P::({list,set}(set)))
local r:= evalf(`+`(map(b-> abs(ln(`*`(b[]))-lnp), P)[]));
end proc:

Min:= proc(S::{list,set}, P::procedure)
local M:= infinity, X:= (), x, v;
for x in S do
v:= P(x);
if v < M then  M:= v;  X:= x  end if
end do;
X
end proc:

ans:= Min(AllP, Var);
[{3, 9, 35}, {4, 8, 28}, {5, 6, 30}]
subsindets(ans, posint, Labels);
[{I, A, F}, {B, E, G}, {C, D, H}]

## Gaussian elimination routine using loops...

I am attempting to write a Gaussian elimination routine to solve a system Ax = b using loops, but I have been having trouble.  Any help would be mcuh appreciated.  Thanks!

## Generation of math apps in dynamic systems engineering...

Maple 2015

ABSTRACT. In this paper we demonstrate how the simulation of dynamic systems engineering has been implemented with graphics software algorithms using maple and MapleSim. Today, many of our researchers the computational modeling performed by inserting a piece of code from static work; with these packages we have implemented through the automation components of kinematics and dynamics of solids simple to complex.

It is very important to note that once developed equations study; recently we can move to the simulation; to thereby start the physical construction of the system. We will use mathematical and computational methods using the embedded buttons which lie in the dynamics leaves and viewing platform cloud of Maplesoft and power MapleNet for online evaluation of specialists in the area. Finally they will see some work done; which integrate various mechanical and computational concepts implemented for companies in real time and pattern of credibility.

Selasi_2015.pdf

(in spanish)

Lenin Araujo Castillo

## How to solve system in that way?...

Is there a command in Maple that directly divides one equation by another and produce the result as one equation directly? I wanted to verify the text book, where it says

x^2-y^2 = a*z^2   ----- (1)
x-y          = a*z       ------(2)
dividing (1) by (2) gives

x+y = z  ---(3)

So I typed this in Maple:

restart;
eq1:=x^2-y^2=a*z^2;
eq2:=x-y=a*z;

But now what to do? I can see the answer in book is correct by doing

solve( {eq1,eq2}, {x,y} );

And adding the solution given above, which shows it is z indeed.  But I'd like to get Maple to generate equation (3) above automatically.  Is this possible?

Maple 2015, windows 7

## Cant open my document...

Hey.

I just got this document and can't seem to open it as a .mv file - I tried to attatch it here, but it wouldn't let me for some reason, so I saved it as a .txt and attatched it instead. Is my file broken, and if so, is there any sort of tool to fix it?

Thanks

## Transitioning to Jordan Form

by: Maple 2015

I have two linear algebra texts [1, 2]  with examples of the process of constructing the transition matrix  that brings a matrix  to its Jordan form . In each, the authors make what seems to be arbitrary selections of basis vectors via processes that do not seem algorithmic. So recently, while looking at some other calculations in linear algebra, I decided to revisit these calculations in as orderly a way as possible.

First, I needed a matrix  with a prescribed Jordan form. Actually, I started with a Jordan form, and then constructed  via a similarity transform on . To avoid introducing fractions, I sought transition matrices  with determinant 1.

Let's begin with , obtained with Maple's JordanBlockMatrix command.

The eigenvalue  has algebraic multiplicity 6. There are sub-blocks of size 3×3, 2×2, and 1×1. Consequently, there will be three eigenvectors, supporting chains of generalized eigenvectors having total lengths 3, 2, and 1. Before delving further into structural theory, we next find a transition matrix  with which to fabricate .

The following code generates random 6×6 matrices of determinant 1, and with integer entries in the interval . For each, the matrix  is computed. From these candidates, one  is then chosen.

After several such trials, the matrix  was chosen as

for which the characteristic and minimal polynomials are

So, if we had started with just , we'd now know that the algebraic multiplicity of its one eigenvalue  is 6, and there is at least one 3×3 sub-block in the Jordan form. We would not know if the other sub-blocks were all 1×1, or a 1×1 and a 2×2, or another 3×3. Here is where some additional theory must be invoked.

The null spaces  of the matrices  are nested: , as depicted in Figure 1, where the vectors , are basis vectors.

 Figure 1   The nesting of the null spaces

The vectors  are eigenvectors, and form a basis for the eigenspace . The vectors , form a basis for the subspace , and the vectors , for a basis for the space , but the vectors  are not yet the generalized eigenvectors. The vector  must be replaced with a vector  that lies in  but is not in . Once such a vector is found, then  can be replaced with the generalized eigenvector , and  can be replaced with . The vectors  are then said to form a chain, with  being the eigenvector, and  and  being the generalized eigenvectors.

If we could carry out these steps, we'd be in the state depicted in Figure 2.

 Figure 2   The null spaces  with the longest chain determined

Next, basis vector  is to be replaced with , a vector in  but not in , and linearly independent of . If such a  is found, then  is replaced with the generalized eigenvector . The vectors  and  would form a second chain, with  as the eigenvector, and  as the generalized eigenvector.

Define the matrix  by the Maple calculation

and note

The dimension of  is 3, and of , 5. However, the basis vectors Maple has chosen for  do not include the exact basis vectors chosen for .

We now come to the crucial step, finding , a vector in  that is not in  (and consequently, not in  either). The examples in  are simple enough that the authors can "guess" at the vector to be taken as . What we will do is take an arbitrary vector in  and project it onto the 5-dimensional subspace , and take the orthogonal complement as .

A general vector in  is

A matrix that projects onto  is

The orthogonal complement of the projection of Z onto  is then . This vector can be simplified by choosing the parameters in Z appropriately. The result is taken as .

The other two members of this chain are then

A general vector in  is a linear combination of the five vectors that span the null space of , namely, the vectors in the list . We obtain this vector as

A vector in  that is not in  is the orthogonal complement of the projection of ZZ onto the space spanned by the eigenvectors spanning  and the vector . This projection matrix is

The orthogonal complement of ZZ, taken as , is then

Replace the vector  with , obtained as

The columns of the transition matrix  can be taken as the vectors , and the eigenvector . Hence,  is the matrix

Proof that this matrix  indeed sends  to its Jordan form consists in the calculation

 =

The bases for , are not unique. The columns of the matrix  provide one set of basis vectors, but the columns of the transition matrix generated by Maple, shown below, provide another.

I've therefore added to my to-do list the investigation into Maple's algorithm for determining an appropriate set of basis vectors that will support the Jordan form of a matrix.

References

 [1] Linear Algebra and Matrix Theory, Evar Nering, John Wiley and Sons, Inc., 1963 [2] Matrix Methods: An Introduction, Richard Bronson, Academic Press, 1969

Need help for manipulating tensor with the physics package.

I ask some questions about this.  But each time, I am refer to the help pages.  If I ask again some help, it is because I can't not start with the information on the help file.  It is written for people that already know General Relativity (GR).

So this time, I have created a document (attach to this post) where I ask specific queations on manipulations.  My goal is to ccrreate a document that I will put on the Applications Center.  I promess that those who will help me on this will be cited in the document.  This way, I hope to create an introduction on how to use tensors for beginner like me.

Then, with this help, I am sure I will be able to better understand the help page of the packages.  I am doing this as someone who is starting to learn GR and have to be able to better understand the manipulations of tensor and getting the grasp of teh meaning of all those tensor.  For exemple, the concept of parallel transport on a curve surface.

Thank you in advance for all the troubling I give you with this demand.

Regards,Parallel_Transport.mw

```--------------------------------------
Mario Lemelin```
```Maple 2015 Ubuntu 14.04 - 64 bitsMaple 2015 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987```

## A question about factoring polynomials, and "type"...

Hi,

I'm relatively new to using Maple.

I'm looking for information on how the "factor" function works. I printed its definition, and it refers to "factor/factor" and I can't find any more information on this. I'd like to know so that I could have more trust that it works correctly. Specifically, I'd like to be able to believe that if it does not factor a cubic, then the cubic is irreducible.

I'm specifically looking for rational roots of cubic polynomials. The "solve" function seems to work, and gives me the roots in terms of square roots, cubic roots and rationals. I have no idea why I should believe that "type(x,rational)" would work when the description of "x" is quite complicated.

Does anyone know anything about how "factor" works, or how "type" works when testing whether an expression evaluates to a rational number? Any information would be much appreciated.

Thanks,
Matt

## Exponentiation in the Physics package...

I ran into a problem with the physics package that I subsequently solved. But I am wondering whether this would be a candidate for an SCR and/or be considered a bug.

The calculation I am trying is actually (so far) very simple.

I define a Hamiltonian H:

H := sqrt(p_^2*c^2+m^2*c^4); # note the square of vector p_

p_:=p1*_i+p2*_j+p3*_k;

H;

So far so good. Now I want to take the differentials of H against the components of p:

diff(H,p1) assuming c::real;

Hmm... I am not sure why the p2 and p3 still show up; but then, the product between the unit vectors should be 0 for different ones and one for equal unit vectors so maybe this is ok.

But H behaves weird: I can simplify it:

but if I try to do anything with it, it barfs:

dH+0;

Error, (in Physics:-Vectors:-+) invalid operation * between vectors _i and _j

As it turns out the issue is the square of the vector p_. Maple (or rather, Physics) does not recognize that it needs to expand p_^2 as p_.p_ and seems to treat is like p_*p_.

I would like Edgardo---& others more experienced with the Physics package than I am---to look at this. I do not understand the Physics package well enough to judge whether overloading the exponentiation operator to make this work is the right thing.

The example works once I replace p_^2 by p_.p_. But the ^2 notation is fairly standard usage so it feels slightly awkward.

Thanks,

Mac Dude.

Derivation_of_H.mw

## How to know what x and y should be...

hello

if you have a function lets say: 2x+1/4-x3

Now if you have to plot the graf, how should you know what the x and y shoud be? I mean you do like: plot(f(x),x=..

what should it be? i find it hard :(

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