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I am writing a procedure that takes the "output" of a call to dsolve (with the options numeric and listprocedure and without specifying a range of integration) as an argument ('dsol') together with a minimally acceptable range of integration ('tf'). The output of the procedure is either the input 'dsol' itself, if dsolve has been able to integrate from 0 to 'tf', or a modified version where the initial conditions have been modified.

Say I want to integrate an ode system [u,v,w...

Hi!

I am bothered by an error that I don't understand. I am trying to write a procedure to solve numerically a delay differential equation "step by step" (for example y'(t)=y(t-1))

here is my code

restart;

y[0]:=t->t; #my initial condition on [-1,0]

p:=dsolve({D(x)(t)=y[0](t-1), x(t0)=x0}, x(t), numeric, parameters=[t0, x0]);

p(parameters=[0,y[0](0)]);

y[1]:=t->op(2,op(2,p(t)));  #y[1](t) is the value of p(t) but in a "readable" format

hi

considering the following ode

eq1 := .6740221708*(diff(f(x), x, x, x))+f(x)*(diff(f(x), x, x))+1-(diff(f(x), x))^2

i solve it by

sol := dsolve({eq1 = 0, f(0) = 0, D(f)(0) = -1.2, (D(f))(b) = 1}, numeric);

this give me one solution but i know that this ode have dual solutions. how can i found all solutions of ODE.

thanks for youe attention in advance

Hello,

I want to calculate the IDs product :

Hi, I have an equation that i need to integrate. Howver, due to the absolute equations I have in it, an analytical integration is not possible. How could i use a numerical method instead?

In matlab, instead of using "int", i use "quad". Is there such a thing in maple?

Please advice. Thanks

Hi all,

I have a function which Maple is happy to integrate from -100 μm to +100 μm,  but won't do between -60 μm and 100 μm.  Screenshot here:

 http://oi39.tinypic.com/34jdif9.jpg

The graph of the function reveals no obvious reason why it shouldn't be able to integrate from +infinity to -infinity (which I'd like to be able to do) and everything in between:

Hi,

i want to use "dsolve({ODE1, IC1, IC2},numeric)" in a procedure. But it has some problems with the curly brace. Is there a special command to replace the curly brace?

Thanks

Hey,

i have 2 differential equations and want to solve the first one when x is positive and the second when x ist negativ. For this problem i wrote the follwing procedure. But when i try i have the posted error. Has someone a good idea to help me?

Thanks a lot

> DGL3 := 10*(D(D(x)))(t) = x(t);

> DGL4 := 10*(D(D(x)))(t)+5000 = x(t);

Tsolver:=proc()
global DG1, DG2, func, var, var_min, var_max, x, Dx, N:

Hey there,

i´ve a numerical solved differential equation and a "normal" equation. How can i calculate the differenz of both?

>S:=0.79*cos(t)+0.3*sin(t);

> DGL1 := 20*(D(D(x)))(t)+10*(D(x))(t)+2500*x(t)+300 = S;
> init := x(1.2) = 0, (D(x))(1.2) = 10.63081252;
> F := dsolve({DGL1, init}, numeric);
>U:=F-S;

> p1 := plot(U, [t, x(t)], 1.2 .. 2, numpoints = 200);
%;
Error, (in plot) two lists...

Hello.

for one of my projects I require to solve differential equations I have obtained from an euler-lagrange system.

I solved them and obtained values of angles and their derivatives as listprocedures. I want however to be able to calculate values for different speeds noted as vx2 and vy2 as well as the angle of the speed verctor wich would be in that case arctan(vy2/vx2). It doesn't seem however that maple is going to do that. It gives me a pretty huge message...

Hi, I am trying to solve the following differential systems using dsolve numeric but there is something wrong with my code.

I am fairly new to Maple and cant work out why it is telling me that it doesnt work. COuld somebody help me?

DifferentialSystem := {diff(r(t),t$2)-r*(diff(theta(t),t)^2=-1000/r^2 ,
                            r(diff(theta(t),t$2)+2(diff(r(t),t)*(diff(theta(t),t)=0,
                            r(0)=sqrt(65), theta(0)=1.446...

I am trying to solve three non-linear coupled initial value problems. The equations are a bit complicated. The MAPLE code is 

restart

with*plots

eq[1] := (1/6)*Ra*v(x)^3*((2*v(x)*w(x)^2*(v(x)^2/w(x)^2-3)*(diff(w(x), x))-6*w(x)^3*(1-v(x)/w(x))^2*(diff(v(x), x)))*A+v(x)^2*w(x)^2*(2*v(x)/w(x)-3)*(diff(w(x), x))-3*w(x)^4*(1-v(x)/w(x))^2*(diff(v(x), x)))/(w(x)^2*(w(x)+2*A)^2*(2*v(x)+3*B))+u(x)

eq[2] := (1/105)*(diff(u(x)^2*(v(x)^2+11*B*v(x)+39*B^2...

hello everyone, I have a numerical methids exam in acouple of hours and I just dound out that maple 11 on our campus computers has an old student package tht doesnt include numercalanalysis , is there anyway to update it ?

myf:=(mu,sigma)->int(exp(-(x-mu)^2/2/sigma^2)/sigma/sqrt(2*Pi)/(1+exp(-x)),x=-infinity..infinity);

plot3d('myf(mu,sigma)',mu=-5..5,sigma=0.5..10);

This plot was never created. I think it's taking too long to evaluate it when it's divegent.

Hi all,

For my research purpose, I need to integrate this function. I understand that there maybe values for which this integration is divegent. But is there a way to look into it? Say creat...

Hi experts,

I would like to ask what is the defult method's name for the numerical integration?

Thanks,