Hi!

 

I have an expression that involves an unknown function, say g:

expr:=a*x[1]+b*x[2]+cx[3]+g(x[1],x[2],x[3]);

where a, b and c are the coefficients I'm actually interested in. These coefficients are not constants but usually expressions in some constant parameters. The function g is an expression involving derivatives of some more fundamental function (in my problem).

Example:

expr:=(q/r-sqrt(2))*x[1] + x[2] - (w*r+4)*x[3] + D(G)(x[1]) - D(G)(x[3]);

Hi

I have som 2D and 3D plots where I would like to change some parameters/constants interactively so that the plot updates automaticly.

I expect that some sort of scroll bar could be used to change a constant interactivly but I need a little help for what it is called in maple and a hint for how it is programmed.

Thanks in advance

regards Brian

Hi all I'd like to construct a phase portrait of a DE system with several different solutions on one plot. To do this I've been using odeplot for each solution and then displaying each plot with display(). Now I'd like for there to be arrows on each solutions, resulting in a phase portrait which will show the direction of phase flow for each orbit, but I couldn't find a way to add arrows to each individual plot. Is there a way to do that ? If not, is there a different approach to achieve this kind of phase portrait ? Thanks LR

 

I want to write a loop, which can give me the appropriate roots of a long equation.

I have tired to use a very simple loop, but the problem is that there are multiple solutions of the equation.

I want a loop which use newton methods to give me the satisfactory roots.

The funtion which I am dealing with is of the form sigma(l).

Plz help me out.

I have attached the maple file.

Hi everyone,

when I use:

c:=2e-6*Unit(A*s/V);

then maple answers with the unit [F]. but when I use:

epsilon[0]:=8.85e-12*Unit(A*s/V/m);

then in the middle of a large document, Maple (Version 12) ignores [m] and still gives me [F]. On a blank (new) document the same command results in correct units [m^-3 kg^-1 s^4 A^2]. The behaviour is reproducible.

anyone knows why?

cheers :-)

 

 

I want to graph a real-valued function e.g. plot y=x^2 from x=1 to 2.  There used to be a function called "plot2D". But it does not exist any more. When I call up the glossary or Help list, I get hundreds of plot-related functions - countourplot, loglogplot, etc - but not a plot for doing a real-valued function.  It is not under with(plots): 

In Advanced Engineering Mathematics there are a lot of math symbols within the text that don't execute. They're not simply an inert math statement, like Int or Diff, but rather the symbolic math used solely as text. How is this done?

Can I store data in a 3D Matrix in Maple ?

 

I want to solve the following PDE with boundary conditions, but unfortunately I do not know the meaning of _F1 and _F2 in this stuation. Would you please help me to find these arbitrary functions?

> PDE := diff(U(y, z), y, y)+diff(U(y, z), z, z) = 0;

> with(PDEtools);

Hi,all, I found a weird problem. When I use alias of RootOf in a procedure, it seem that it cannot work correctly. The code is as following: > restart; > cf := proc (n, ir) local P; alias(x = RootOf(ir)); P := evala(Expand(x^4)) mod 2; print(P); end; >cf(4,x^4+x+1); x^4 ---------------------> should be x+1 However, when I use it in seperate commands, it works fine. > restart; >alias(x = RootOf(x^4+x+1)); >P := evala(Expand(x^4)) mod 2; >print(P); x+1 I have no idea what is wrong here Thanks Gepo

The following program produces a plot in the 4th quadrant.

S1:=unapply(u*FresnelS(u)+((1/Pi)*cos((1/2)*Pi*u^2))-(1/Pi),u);

C1:=unapply(u*FresnelC(u)-((1/Pi)*sin((1/2)*Pi*u^2)),u);

R1:=1;

u1:=evalf(sqrt(0.4));

E1:=evalf(Pi*R1*S1(u1)+R1);

D1:=evalf(Pi*R1*C1(u1));

with(plottools);

with(plots);

c1 := circle([D1, 0], R1);

a:=evalf(Pi*R1*u1);

p1:=plots[display](plot([1+a*FresnelC(u),a*FresnelS(u)-E1,u=0..u1]),c1,scaling=constrained);

p3:=plot(0,x=-1..0);

display(p1,p3);

 

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My friends, I am trying to compress a very long equation. Can any one help me to make it possible to compress the equation, means to write it in a very very simplified form. The real reason for this hardwork is that the equation is very long to write it in latex.

Your quick response is required.

Thanks to all

Hi everybody and thanks a lot for your help!

My problem is the following: I would like to draw a phase diagram for a system of 3 differential equations. So far this is not a problem but I would like to have the arrows of the vector field included in the diagram, like it is possible for systems of 2 diff. equations. Is that possible?

I use DEPlot3d, I suppose that is the correct tool?

Thanks and regards

Hans

I have the above program

S1:=unapply(u*FresnelS(u)+((1/Pi)*cos((1/2)*Pi*u^2))-(1/Pi),u);

C1:=unapply(u*FresnelC(u)-((1/Pi)*sin((1/2)*Pi*u^2)),u);

R1:=1;

u1:=evalf(sqrt(0.4));

E1:=evalf(Pi*R1*S1(u1)+R1);

D1:=evalf(Pi*R1*C1(u1));

with(plottools);

with(plots);

c1 := circle([D1, E1], R1);

a:=evalf(Pi*R1*u1);

plot([a*FresnelC(u),a*FresnelS(u),u=0..u1]);

p1:=plots[display](plot([a*FresnelC(u),a*FresnelS(u),u=0..u1]),c1,scaling=constrained);

p3:=plot(0,x=-1..0);

display(p1,p3);

I have found eigenvalues of a  2x2 matrix A, these are displayed in a vector. eg.

a + sqrt(b)

a - sqrt(b)

Is there any way I can write code which will find the difference between them? At the moment I'm doing it manually and it is taking a lot of time as I have many matrices.