Dear Friends,

I am solving 6 ODEs using maple15. then i got this error. anyone know abou this? thank you.

problem2.mw

Download problem2.mw

When I take the derivative of this function wrt p, I am getting this:

Why the program gives , instead of only

Sorry for the format, I just copy and paste.

Thanks,

Hi,

I want to display several plots insequence and tried creating a list of polygonplot3d objects called "plotlist" and using them as an argument like this:

display(plotlist)

which triggered the error message:

Error, (in plots:-display) expecting plot structure but received: plotlist

Where's my mistake and how could I achieve the desired outcome? (displaying polygon3dplots in sequence)

Best Regards

I have generated a picture using pointplot and display that creates a grid of colors based on the angle between vectors and (1,0) in R^2. Each angle is given a unique color via the HSV color space. I would like to provide a legend explaining the colour, something along the lines of

red (brown) green (blue) red
0                Pi                 2*Pi

and possibly

red       (brown)       green 
angle1                     angle2   

Is there an easy way to do this, or will I have to mess around with a custom pointplot/textplot solution?

Good day everyone,

Please I do get numerical output/values in this solution U1.mw

Best regards

please help me a bout:

> u := am+bm*m0*x(t)+cm*n0*y(t);
> v := an+bn*m0*x(t)+cn*n0*y(t);
> eq1 := diff(x(t), t) = 2*A*(sinh(u)-x(t)*cosh(u));
> eq2 := diff(y(t), t) = 2*A*(sinh(v)-y(t)*cosh(v));
> init := x(0) = X, y(0) = Y;
> sol := dsolve({eq1, eq2, init}, {x(t), y(t)});
> param := A = 1/2, am = 0, bm = 1.2*exp(-4), cm = .5*exp(-5), m0 = 10000, an = 0, bn = -exp(-4), cn = 1.2*exp(-3), n0 = 1000;
> ;
> save u, v, param, " narm.sav";
Warning, unassigned variable `u` in save statement
Warning, unassigned variable `v` in save statement
Warning, unassigned variable `param` in save statement
> init := x(0) = 0, y(0) = 0.1e-1;
> eq1 := subs(param, eq1);
> eq2 := subs(param, eq2);
> sol := dsolve({eq1, eq2, init}, {x(t), y(t)}, numeric);
> with(plots);
> odeplot(sol, [x(t), y(t)], 0 .. 60, numpoints = 300, view = [-1 .. 1, -1 .. 1]);

How do I control colors in such Maple program using plot3d? Is it possible to define the conditions?

> restart: with(plots):
      mandelbrot := proc(x, y)
     local c, z, m;
     c := evalf(x+y*I);
     z := c;
     for m from 0 to 30 while abs(z) < 2 do
        z := z^2+c
        od;
        m
     end:
 >    plot3d(0, -2 .. 0.7, -1.2 .. 1.2, orientation=[-90,0], grid=[40, 40], 
       style=point, scaling=constrained, color=mandelbrot);

I have a (251*1) vector for which I need to compute the cumulative sum. I'm currently using :

s:=Statistics[CumulativeSum](prices[1..251,1])

defined under the Statistics package but this method doesn't return an output, even though the argument passed is a vector.

Is there another method I can use?

In my  Standard GUI Maple 2015 (32 bit)  on Windows 8.1  plots[spacecurve]  command does not work:

plots[spacecurve]([cos(t), sin(t), t], t = 0 .. 2*Pi);

Can someone confirm this bug?

dx/dt=2x(1-x/2)-xy, 

dy/dt=y(9/4 -y^2)-(x^2)y 

hi. please help me about modeling population migration. i am writing a sample for drawing plot in maple, however maple has not any error, but working incorrectly. my program is:

> u := am+bm*m0*x*t+cm*n0*y*t;
> v := an+bn*m0*x*t+cn*n0*y*t;
> eq1 := diff*(x*t, t) = 2*A*(sinh(u)-x*t*cosh(u));
> eq2 := diff*(y*t, t) = 2*A*(sinh(v)-y*t*cosh(v));
> init := x*0 = X, y*0 = Y;
> sol := dsolve*({eq1, eq2, init}, {x(t), y(t)}, numeric);
> param :=A=1/(2) ,am=0 , bm=1.2*(e)^(-4) ,cm= 0.5*(e)^(-5) ,;
> m0 = 10000, an = 0, bn = -exp(-4), cn = 1.2*exp(-3), n0 = 1000;
> save u, v, param, " narm.sav";
> init := x*0 = 0, y*0 = 0.1e-1;
> eq1 := subs*(param, eq1);
> eq2 := subs*(param, eq2);
> sol := dsolve*({eq1, eq2, init}, {x(t), y(t)}, numeric);
> with*plots;
> odeplot*(sol, [x*t, y*t], 0 .. 60, numpoints = 300, view = [-1 .. 1, -1 .. 1]);
> odeplot*(sol*d, [t, x*t, y*t], 0 .. 60, numpoints = 300, orientation = [70, 55], colour = black, axes = normal);
> init := x*0 = -1, y*0 = 1;
> sold := dsolve*({eq1, eq2, init}, {x(t), y(t)}, numeric);
> odeplot*(sold, [x*t, y*t], 0 .. 60, numpoints = 300, view = [-1 .. 1, -1 .. 1], color = black);

I have two polynomials, say

x(t) = a[0] + a[1]t + a[2]t^2

y(t) = b[0] + b[2]t + b[3]t^2

with the following conditions, x(0) = 2 and y(0) = 1. The polynomial are related by

x'(t) = y(t)

y'(t) = x(t)

and x(0) = 2, y(0) = 1.

One can show that the solution is x(t) = 2 + t + t^2 + O(t^3) and y(t) = 1 + 2t + 0.5t^2 + O(t^3).

I am trying to write something so that it works on a larger system. I have a set of nonlinear DEs which i want to solve this way. Here is a sample code of a much simplifed problem.

See the uploaded file for details.

edit: link is reparied. I uploaded the wrong file initially

edit2: Some improvements were made, but Maple still not returning.

2-2_tests_01.mw

I've got an excel file and a maple file saved in the same folder and am trying to import the contents of the excel file using  the Exceltools[Import]("name of file.extension") command as given in the manual but it doesn't seem to work. I've also tried copying the entire path of the file in the argument but that doesn't seem to work either. What am I doing incorrectly?

Is it possible to use an option similar to range when using lsode method for dsolve? The ODEs I am trying to solve is stiff and will not work with the flag stiff=true or with method=rosenbrock unless i set Digits:=20. I want to avoid doing that as much as possible, since I believe wit will be very taxing, computationally. I have a very large systeom to solve. I found that method=lsode works with the default Digits=15. 

However I need to have the solutions in a given range stored for future access and manipulations. Using range gives me an error: 

Error, (in dsolve/numeric/an_args/lsode) lsode keyword was range, optional keyword must be one of 'ctrl', 'initial', 'itask', 'output', 'procedure', 'procvars', 'start', 'number', 'abserr', 'relerr', 'maxfun', 'minstep', 'maxstep', 'initstep', 'startinit', 'implicit', 'optimize', 'complex'

I cannot figure out how to use range or something similar with lsode. Anyone knows? 

Hello,

I am solving a large system of ODEs, using the following command,

> Sol := dsolve({seq(ode[j], j = 0 .. 21), seq(v[j](0) = 0, j = 1 .. 21), v[0](0) = 1}, [seq(v[j](t), j = 0 .. 21)]);

>

and then plot the quantities I want by something like

> plots:-odeplot(Sol, [t, v[3](t)+v[5](t)], t = 0 .. 1.5);

My problem is that, I do not know a priori which quantity I want to plot, and plotting using above method requires solving the ODEs each time separately, which takes a long time.

So I was curious if there is a scheme that I can solve my system for once and for all, and then plot any quantities that I would like to see.