Hellow.
Is Maple understand the symbol f(i,j), f[i,j], f:=-->(i.j) and f_{i,j}  in the same way or in different way.

How to convert a system of differential equations to a matrix?

can infolevel show this matrix during the process?

Using plottools[line], the option for coords does not work.  It remains in cartesian coordinates regardless of the coords specification.

Dear Maple experts,

I am struggling with a difference between the symbolic and numerical solution of an eigendecomposition of a symmetric positive definite matrix. Numerically the solution seems correct, but the symbolic solution puzzles me. In the symbolic solution the reconstructed matrix is different from the original matrix (although the difference between the original and the reconstructed matrix seems to be related to an unknown scalar multiplier.

restart;
with(LinearAlgebra);
Lambda := Matrix(5, 1, symbol = lambda);
Theta := Matrix(5, 5, shape = diagonal, symbol = theta);
#Ω is the matrix that will be diagonalized.
Omega := MatrixPower(Theta, -1/2) . Lambda . Lambda^%T . MatrixPower(Theta, -1/2);
#Ω is symmetric and in practice always positive definite, but I do not know how to specify the assumption of positivess definiteness in Maple
IsMatrixShape(Omega, symmetric);

# the matrix Omega is very simple and Maple finds a symbolic solution
E, V := Eigenvectors(Omega);

# this will not return the original matrix

simplify(V . DiagonalMatrix(E) . V^%T)

# check this numerically with the following values.

lambda[1, 1] := .9;lambda[2, 1] := .8;lambda[3, 1] := .7;lambda[4, 1] := .85;lambda[5, 1] := .7;
theta[1, 1] := .25;theta[2, 2] := .21;theta[3, 3] := .20;theta[4, 4] := .15;theta[5, 5] := .35;

The dotproduct is not always zero, although I thought that the eigenvectors should be orthogonal.

I know eigenvector solutions may be different because of scalar multiples, but here I am not able to understand the differences between the numerical and symbolic solution.

I probably missed something, but I spend the whole saturday trying to solve this problem, but I can not find it.

I attached both files.

Anyone? Thank in advance,

Harry

eigendecomposition_numeric.mw

eigendecomposition_symbolic.mw

Hello, I'd like to generate some data from an audio file, like get the amplitude and the time, so that I can plot it with x = time and y = amplitude, do you know how to do that ?

restart:
tf:=2:
n:=2:
X[1]:=t->t^2:
A[1]:=diff(X[1](t),t,t):
plot(A[1](t),t=0..tf,labels=["Time t","n times derivative of X[1](t)"]);

I have a code like above. I run it. Then,

in the labels; it was written "n times derivative of X[1](t)"] why not "2 times derivative of X[1](t)"]) ? and why was not the subscript appeared ? I mean that I want to see X₁ instead of  X[1]?

Help me please.

Thank you.

Hi Maple Community,

I just got my Maple licence and currently I'm going thorugh some basic tutorials in which I've encountered a problem I can't seem to fix:

I'm trying to use the 'LinearSolve' solver as it is shown in the examples on the Maplesoft.com support page:

But I can't seem to get Maple to display a result like it is shown in the picture above.

Instead Maple displays this:

I would be very grateful if someone could tell me what I'm doing wrong.

regards, Alex

I want to use the solutuion of a DE as a function, including the possibility to plot it.

I have found out that the following comands work, but I cannot undesrtand why. Is there a simpler way?

Truly, Roberto R. Baldino

sol := dsolve({eq, icon}, i(t));
i := unapply(eval(i(t), sol), t);
plot(i(t), t = 0 .. 20, view = [-1 .. 20, -3 .. 3], gridlines);

If not define a procedure

just pass day(hello(a,b), c)

as parameter how to get hello , this function name and day this function name

Hello everybody,

i'm searching for a data-structure similar to the C++ std::unordered_map, so that the access time is konstant O(1) and no matter about the order. What access time does a table() in Maple have, it seems to be not O(1).

If algebra use factorise method,

Which method do maple use to dsolve differential equation?

I am trying to perform the following integral:

Which spits the integral back out at me.

I've also tried

Which, again, spits the integral back out at me.

My last attempt was this

Which... Still spit back out the integral.

Is there something special I should be doing for functions I'm integrating with a natural log? I need to get an exact value for this, not an approximation (because I am trying to check the accuracy of an approximation with this!).

Thanks!

Hi

How call each column of matrix by loop?

Hello there, my first time posting in this forum and using Maple, so sorry if I make some mistakes.

I'm trying to read a wav audio file, but there's this weird error that I can't understand : 

with(AudioTools);

[Audio, Clip, Convolution, Create, Duration, Extract, FormatFromName, Formats, Modulate, Normalize, Play, Preview, Read, Record, Resample, Scale, ToMono, ToStereo, Write]


audio := Read("C:\\Users\\Simon\\Desktop\\Test\\440.wav");

Error, (in readbytes) WAVE Error: unexpected end of file

Do you know what it can mean ? I'm sure it's a wave file, so I don't really get it

hi,

i'am beginers in  the maple programmation, i want to solve the einstien equation in the spherical coordinate,