I have the following problem with the commands "Infinitesimals" and "InvariantSolutions". After using them to a system of firsst-order PDE's, the following message appears:

 Error, (in table["k"]) expected a request of prolongation w.r.t one of 2 independent variables; received a request w.r.t the (inexistent) 4th one

Does anybody know, what this message means ? I am a beginner with the commands "Infinitesimals" and "InvariantSolutions"...

f is a piecewise smooth function of exponential order. find the function f

exp(-3*t)+t^3+int((7-x+(17/2)*x^2-(35/3)*x^3)*f(t-x), x = 0 .. t)

i need some help. thx

Hi all,

I have been trying for some time create an animation of a 3d plot I created rotating about the z-axis in Maple 15. I tried using the usual

animate(plot3d,f(x,y),orientation=[A,10],A=0..5)

but not only does that produce an error when I try to do the same thing with an implicitplot3d function, it also doesn't work when I try to animate multiple plots in the same graph, whether implicit functions or regular plot3d ones. I am creating a model...

I am looking at various ways to generate surfaces in a cylindrical coordinate system. When using the cylinderplot( ) command, the default color scheme is acceptable. However, when using the implicitplot3d( ) command, the surface comes out very dark. I've played with a few color/lighting options, but I'm still not able to have the implicit3d plot look anything like the cylinder plot. Can someone suggest any color/lighting/shading options that might acheive this. My initial results are attached.

Hi 

I have a problem with my three task to do in Maple (ver.16)

1. I have a differential equations:

dy/dt=-y, y(0)=1

How to do it in Maple (using Dsolve command) and how to draw this ?

2. Solve and draw second-order differential equation :

d²y/dt²+y(t)=sin t   ; y(0)=0 ; y'(0)=1

3. Solve and draw equation:

Often when I have an integral maple returns the result as a limiting expression.

However the limit's value is clear. Is there any way to force maple to evaluate the limit?

Any help is greatly appreciated.

Hi

I'm building my set of functions that will deal with geometries of different dimentions, thus I need to deal with/pass to my functions arrays of different dimentions count, I can't figure out how I can build arrays of, for example, n dimentions, where in each dimention m rows, currently I'm using if..elif on array dimention count that I'm retriving by using something lilke n=Size(Size(A),2) where A is the passed array, then I constracting my new arrays by B=Array(1..m,1..m... n-times...

Hi experts!

Suppose we want to plot a function depending on integral evaluation, like

> S := Int(sin(sin(x+u)+sin(y-u)),u=0..Pi);
               /Pi                                 
             ...

In a folder I have several worksheets in maple. Each worksheet is named Forum, plus a consecutive number. Internally each worksheet has the following structure:

I would like, from a Maple worksheet, perform a query that would allow me to make a table of contents or index of the information found in the header of each section of all worksheets contained in the folder

Good afternoon everbody,

I am trying to make a rational interpolation from the data of a function (values of the function for different points).
I tried to do it with the RationalInterpolation command but it requires too much time. Then I chose to solve the problem with the NonlinearFit command but the result varies a lot if I a change the basic function I want to approach and I always get a warning message: limiting numer of iterations reached.

Now we turn to an example of the usage of the Dragilev method with Maple. Let us consider the curve
from
http://www.mapleprimes.com/questions/143454-How-To-Produce-Such-Animation .

Its points can be found by the Dragilev method as follows.

This is an effective method of solving systems of  N nonlinear and nonalgebraic equations in N+1 real-valued variables:
F(x)=0, where F=(f1,f2,..., fN) and x=(x1,x2,...,xN+1). (1)               
                                                                  
All the functions fj(x) are assumed to be continuously differentiable in some domain D in R^(N+1).
In general, such systems have an infinite set of the solutions which form a space curve in R^(N+1).
 The Optimization and DirectSearch solvers have difficulties with it.
The idea of the Dragilev method consists in the following. Let us assume that the space curve (1) can be parametrized through the  parameter t
which can be taken as the  length of the arc (for example, see http://en.wikipedia.org/wiki/Curve ).
That presentation provides to avoid the difficulties associated with self-intersections and singularities.
We will obtain the coordinates of the points of the space curve under consideration as the solution
of the Cauchy problem for certain system of ODEs. We put the coordinates of a known point of (1) as the initial conditions.
The system of ODEs is obtained by the differentiation  with respect to t:

We treat (2) as a linear system in the derivatives diff(xj(t),t),j=1..N+1. In general, its solutions form an infinite set.
We choose the  solution of (2) as follows. We put diff(xN+1)= -Determinant(Matrix(n, (i,j)->diff(fi(x),xj))).
This is one of the key points of the method under consideration.
Next, we find diff(xj,t), j=1..N. At last, we numerically solve that system of ODEs, obtaining an array of points.
 The general case of a system of N nonlinear  equations in N variables
G(y)=0, where y=(y1, y2, ..., yN), G=(g1,g2,..., gN) (3),
is reduced to the previous one by homotopy. We choose a point y0= (y01, ..., y0N) and consider the system
G(y)- v*G(y0)=0 (4)
of N equations in N+1 variables (v is taken as  a dummy variable). Changing v from 1 to 0, we arrive to (3).
We don't consider any mathematical justification of the above pattern here as that does not deal with Maple.
I would like to point out the sites

http://forum.exponenta.ru/viewtopic.php?t=3892 and
http://forum.exponenta.ru/viewtopic.php?t=11284 , where the Dragilev method is discussed. Unfortunately, in Russian.
The googling of "Dragilev" and "Draghilev" does not produce many info.
A short biographical sketch: Dr. Anatoliy Vladimirovich Dragilev (1923 - 1997) was a professor at  Rostov State University in Russia.
See his articles here: http://www.mathnet.ru/php/person.phtml?&personid=32359&option_lang=eng and
http://www.zentralblatt-math.org/zmath/en/search/?q=au%3A%22dragilev%2C%20a*%20v*%22 .
 

I am very grateful to Professor Alexey B. Ivanov, who is an enthusiast of the Dragilev method, for the very useful discussions.

hi,

I have created a large matrix (31  times 4) using Maple 15. some of the columns of the matrix contains a long list.

I would like to save the contents of the matrix to either MS-Word or Excel. I tried right-click>Browse>export and saved it as an excel file. But the data in the columns consisting the long lists is lost in the saved file.

1)Is there any other way I can save the contents of the matrix.

2) the matrix seems too large...

Hi,

I meet a problem when I want to find the derivative of an integral with parameters when th eintegral has an option for numerical evaluatio.  For example

>  S := Int(sin(a*x)/x,x=0..infinity,method=_DEFAULT);

> diff(S,a);

Error, (in diff/Int) invalid Int(...) format

What is the correct syntax ?

Thanks, 

 Dan

Thank you for the suggestions. Float command helped me a lot for real matrices but when I have imaginary numbers in my matrix it gives me error.  

 after I construct the matrix A I do = implies  Af:= Matrix(A, datatype= float):

That gives me error message ' Unable to store 0.-18844.3412345686*I ' when datatype=sfloat'    is there a solution for that like complex_float "? I  looked at Maple help but I could not find...