## solve ode srm motor...

How I can solve it for P?

P=i^(2)r+(&DifferentialD;)/(&DifferentialD; t) (1/(2)l(tetha)i^(2))+1/(2)i^(2)(&DifferentialD;l(tetha))/(&DifferentialD; theta) w

attach i(t) "corrente", l(t) "induttanza", theta "angular", w "rotary speed"graph of funtions

thanks

## Symbolic cut-off of high-order terms...

Hi! I have a variable polynomial expression and I want to cut off all the terms of order 3 and more, for every product of variables.

For example consider the polynomial P = x + y + a*x^2 + b*x^3 + c*x*y + d*x^2*y + e*x*y^2 + y^2, I want an operation who returns me a*x^2 + c*x*y + y^2

(terms for which the sum of exponents in x and y exceeds or less two are being deleted)

Is it possible?

## how i can write this line ''for'' in maple?...

hi..

how i can write this line ''for'' in maple?

thanks..

 TopEdge = "C"; BottomEdge = "C"; LeftEdge = "C"; RightEdge = "C";

## Error, (in eval/diff) invalid input: diff received...

hi .in substuting in ode equation i encounter with error

Error, (in eval/diff) invalid input: diff received (f1[i+1, i]-2*f1[i, i]+f1[i-1, i])/h^2, which is not valid for its 2nd argument

thanksh_2.5_eq4.mw

 (1)

 (2)

 (3)

## nonlinear fit gives the right fit, but wrong param...

hello im currently working on a project and im fitting some non-linear data with the follwing model:

model:= 1.*10^5*exp(-t*k-*t/B)

where B and k are the unkown parameters.

i have the following data:

X=<0,2,4,6,8,10>

Y := <100000, 86089.76983, 74114.4849, 63804.98946, 54929.56828>

if i do the fit like this: fit(model,X,Y,t) i get a fit that looks like this:

100000*exp(-0.520664970792415e-1*t) which i alright. however when i try to get the parameters i get something like this

fit(model,X,Y,t,output=[parametervalues])

[B = .999563650781966, k = -.948370042622550] - when i define k=0.05 however i get [B = 483.910474528817], which is the right parameter.

insereting the two different sets yields:

1) k=0.05, B = 483.910474528817 -> 100000*exp(-0.520664970792415e-1*t) (good aprox to the fit)

2) B = .999563650781966 and k = -.948370042622550 -> 100000*exp(-0.5206649794e-1*S) (way off)

how is this possible anyone able to help, been sitting with this for days now?

## Maple 2016 not starting...

Hallo,
I got problem with starting maple 2016, when I click on the app files, it thinks for a second then nothing happens, I have tried to uninstall and install again, but no defference. I am not getting any error at any point, that is why it is hard to fix. maybe it has to do with java, jre or PATH?

## Corrupt Maple document (I know that this exact pro...

https://www.dropbox.com/s/zpj7kudgn3gikfa/INS%20-%20Bygninger%20energibehov.mw?dl=0

https://www.dropbox.com/s/vj0t0p3r9stoy3c/INS%20-%20F%C3%B8ringsveje%20og%20indeklima.mw?dl=0

I have seen threads where this has been solved, but i do not know how to do it.

It happened to both files, after restarting my computer.

Are anyone willing to help me?

## complex tensor expression with Pauli matrices...

I attempt to understand is it possible whether to calculate the next expression by means of mathematica:

where

{,}- anti-communicator;

a=0,1,2,3;

\tau^{0}-unity matrix; \tau^{i} - Pauli matrix;

and:

finally - Levi-Civita symbol; -Hermitian conjugation.

Thank you for your kind replies .

## How to obtain accurate rotation matrices?...

Hey guys,

I'm trying to build up some program to manage my composites data. But I am struggling with my compliance/stiffness in the global coordinates:

-Basically, I have the lamina's properties in local coordinates.

-When I make walls out of them with 30degress fibers orientation, I need to rotate the local stiffness several times to get the the stiffness of that particular wall.

-While I do understand the concept and manage to get the final rotation matrix correctly, I often find myself making mistakes regarding the sense of rotation of my local axis relatively to the global one.

I try to stick with one direction of rotation but if Maple has a smart way whereas I can plug in the initial configuration of the local coords relatively to the global one, show the final configuration (local aligned to the global), and get the rotation matrix that made it happen, it would be more helpful.

Thank you

Update:

I enclosed an example of the kind of operations I do:

And here is the kind of code I'm using:

 > restart:
 > with(LinearAlgebra):
 > Stiffness:=Matrix(6,6): Stiffness:=Matrix(6, 6, {(1, 1) = 20.4, (1, 2) = .537, (1, 3) = 1.01, (1, 4) = 0., (1, 5) = 0., (1, 6) = -0., (2, 1) = .537, (2, 2) = 1.59, (2, 3) = .73, (2, 4) = 0., (2, 5) = 0., (2, 6) = -0., (3, 1) = 1.01, (3, 2) = .73, (3, 3) = 2.86, (3, 4) = 0., (3, 5) = 0., (3, 6) = -0., (4, 1) = 0., (4, 2) = 0., (4, 3) = 0., (4, 4) = 1.5, (4, 5) = 0., (4, 6) = -0., (5, 1) = 0., (5, 2) = 0., (5, 3) = 0., (5, 4) = 0., (5, 5) = 2., (5, 6) = -0., (6, 1) = 0., (6, 2) = 0., (6, 3) = 0., (6, 4) = 0., (6, 5) = 0., (6, 6) = .8});
 (1)
 > Q1:=Matrix(3,3): Q1[1,1]:=sin(Pi/4); Q1[1,2]:=0; Q1[1,3]:=cos(Pi/4); Q1[2,1]:=cos(Pi/4); Q1[2,2]:=0; Q1[2,3]:=-sin(Pi/4); Q1[3,1]:=0; Q1[3,2]:=1; Q1[3,3]:=0;
 (2)
 > Q1;
 (3)
 > Q2:=Matrix(3,3): Q2[1,1]:=0; Q2[1,2]:=0; Q2[1,3]:=1; Q2[2,1]:=1; Q2[2,2]:=0; Q2[2,3]:=0; Q2[3,1]:=0; Q2[3,2]:=1; Q2[3,3]:=0;
 (4)
 > Q2;
 (5)
 > Q3:=Matrix(3,3): Q3[1,1]:=0; Q3[1,2]:=-1; Q3[1,3]:=0; Q3[2,1]:=1; Q3[2,2]:=0; Q3[2,3]:=0; Q3[3,1]:=0; Q3[3,2]:=0; Q3[3,3]:=1;
 (6)
 > Q3;
 (7)
 > S1:=Transpose(Q1); S2:=Transpose(Q2); S3:=Transpose(Q3);
 (8)
 > S4:=Multiply(S3,S2);
 (9)
 > S5:=Multiply(S4,S1);
 (10)
 > R:=Matrix(6,6): R[1,1]:=S5[1,1]^2; R[1,2]:=S5[1,2]^2; R[1,3]:=S5[1,3]^2; R[2,1]:=S5[2,1]*S5[1,1]; R[2,2]:=S5[2,2]*S5[1,2]; R[2,3]:=S5[2,3]*S5[1,3]; R[3,1]:=S5[2,1]^2; R[3,2]:=S5[2,2]^2; R[3,3]:=S5[2,3]^2; R[1,4]:=2*S5[1,2]*S5[1,3]; R[1,5]:=2*S5[1,1]*S5[1,3]; R[1,6]:=2*S5[1,1]*S5[1,2]; R[2,4]:=S5[2,2]*S5[1,3]+S5[2,3]*S5[1,2]; R[2,5]:=S5[2,1]*S5[1,3]+S5[2,3]*S5[1,1]; R[2,6]:=S5[2,1]*S5[1,2]+S5[2,2]*S5[1,1]; R[3,4]:=2*S5[2,2]*S5[2,3]; R[3,5]:=2*S5[2,1]*S5[2,3]; R[3,6]:=2*S5[2,1]*S5[2,2];
 > R[4,1]:=S5[3,1]*S5[1,1]; R[4,2]:=S5[3,2]*S5[1,2]; R[4,3]:=S5[3,3]*S5[1,3]; R[4,4]:=S5[3,2]*S5[1,3]+S5[3,3]*S5[1,2]; R[4,5]:=S5[3,1]*S5[1,3]+S5[3,3]*S5[1,1]; R[4,6]:=S5[3,1]*S5[1,2]+S5[3,2]*S5[1,1]; R[5,1]:=S5[3,1]*S5[2,1]; R[5,2]:=S5[3,2]*S5[2,2]; R[5,3]:=S5[3,3]*S5[2,3]; R[5,4]:=S5[3,2]*S5[2,3]+S5[3,3]*S5[2,2]; R[5,5]:=S5[3,1]*S5[2,3]+S5[3,3]*S5[2,1]; R[5,6]:=S5[3,1]*S5[2,2]+S5[3,2]*S5[2,1];R[6,1]:=S5[3,1]^2; R[6,2]:=S5[3,2]^2; R[6,3]:=S5[3,3]^2; R[6,4]:=2*S5[3,3]*S5[3,2]; R[6,5]:=2*S5[3,1]*S5[3,3]; R[6,6]:=2*S5[3,1]*S5[3,2];
 (11)
 > print(R);
 (12)
 > RTrans:=Transpose(R);
 (13)
 > Stiff1:=Matrix(6,6): Stiff1:=Multiply(Stiffness, RTrans);
 (14)
 > StiffnessW1:=Matrix(6,6): StiffnessW1:=Multiply(R,Stiff1); evalf(StiffnessW1,3);
 (15)
 >

It is decent enough to get results if human mistakes don't happen when it comes to rotation orientation (which tends to happen more often than not).

I am aware though that it is not written with wits or in an efficient format. If you have a suggestion, Im all ears.

Thanks again

## Scientific output...

Is there a way to change the numeric formatting of 'Scientific' to use a cdot instead of a cross to represent multiplication?

## How do I integrate a large set of datapoints....

Hello!

I got a set of data imported from excel which is of the size 2001x2. I've use DataPlot to plot the graph of this data but I can't seem to find a way to integrate it. I've used BSplineCurve to make the discreate values continious but I cant seem to integrate this new curve. Can someone please give me a solution or an alternative way to find an approximative way to find the area under the curve.

Thanks

## animating a cylinder bounded by a sphere...

Guys

I can't seem to work out how the cylinder in my animation won't extend to of the bottom of the sphere initially. and how to make it stop at the maximum volume coordinates.

cylinder_in_sphere_ani.mw

## How do I factor a vector out of a matrix...

Hey guys,

I have this (6x1) matrix:

And I wish to factor a vector of the recurring terms out of it, this particular vector:

So that I end up with a (6x6) Matrix multiplied to that vector.

Thank you

## Bug in limit

Maple 2016

Let us consider

restart;
MultiSeries:-limit(sin(n)/n, n = infinity, complex);
0

The answer is wrong: in view of the Casorati-Weierstrass theorem the limit does not exist. Let us try another limit command of Maple

limit(sin(n)/n, n = infinity, complex);

(lim) (sin(n))/(n)


which fails. Therefore, Maple user does not obtain the correct answer.

## How do I remove all files associated with Maple to...

Hi

I have this problem that my computer crashed during Maple 2016.1 to 2016.2 update.

Now it won't start at all.

I have tried reinstalling Maple several times, tried not updating to 2016.1 and running the program as vesion 2016.0.

I get this error in my eventlog, when I try to run the program.

Name of program errors: javaw.exe, version: 8.0.1020.14, timestamp: 0x576af3f4
Name of the module with error: nvSCPAPI64.dll, version: 7.17.13.7849, timestamp: 0x588218a5
Exception code: 0xc0000409
Displacement by mistake 0x0000000000034b2f
Process ID 0x166c
Program path: E: \ School Program Files \ Maple 2016 \ jre \ bin \ javaw.exe
Module path: C: \ Program Files (x86) \ NVIDIA Corporation \ 3D Vision \ nvSCPAPI64.dll
Report ID: d52f952d-8fd2-4130-890a-196e6a7bdc92
Full name of the program with the error:
Relatively application ID for program errors:

So as my titel suggests I need help to remove all files associated with Maple so I can install the program anew. It has worked fine for over a year so far. Only stopped working after that crash.

I have even tried installing the older version, Maple 2015 and it doesn't work either, so I am guessing the files which are corrupted aren't removed during a normal uninstall process, and they are shared among the versions of the program.