1. nonlinear ODE with parameter "epsilon"

(x^n +epsilon*y(x))dy/dx + n*x^(n-1) * y(x) =m*x^(m-1) ; y(1)=b>1

where n=2,3,4,.. and m=0,1,2,3,...

2. Duffing equation with parameter "epsilon"

d^2 y(x)/dx^2 + y(x) + epsilon*y(x)^3=0 ; y(0)=A ; y'(0)=0

Hi

I want to make my maple.ini file so that it sets plotoptions(discont=true) as starndard, so that I don't have to write it all the time.

I did it a couple of years ago, but can't make it work now.

Hope some of you can help me.

Regards

Michael

Hi,

I'm plotting this function of (x) which is very complicated expression anyway I plotted it..Now I want to plot the f(x)/max value of f(x)???

I appriciated for any advice...

Hi, im new with maple

so I am still a bit confused with how to use it..

i have an nonlinear ODE with parameter "b"

(x+b*y(x))dy/dx + y(x) =0 ; y(1)=1

if i want b=0.1 and x=0, 0.1, 0.2, ..,1

how do i

M = (1+y^2)/((x^2+1)*(1+z^2))

Anyone have any background knowledge on the above 3D polynomial?  Assuming all 4 parameters are real I ploteed some 3D plots & some interesting surfaces are generated.  I imagine this has some physical application.  If anyone has some knowledge on this please respond & include any references you might know of.

Thanks

I tried using maple to solve the below system of Partial differential equations but itzz not jst coming out... any assistance will be appreciated (post the maple codes if used)

sys2 := -(diff(u(y, t), y, y)) + S*(diff(u(y, t), y)) + diff(u(y, t), t) + M.u(y,t) + (u(y,t)/k)-theta(y,t) = 0,
 -(diff(theta(y, t), y, y))/Pr + diff(theta(y, t), t) + S*(diff(theta(y, t), y)) = 0

The variables are... u(y,t) and theta(y,t)

The initial conditions are;

Hello,

I am having some trouble with a recursive formula which I instead turned into a loop to avoid any errors. I defined an array before starting the loop and defined the last index as a floating number (this will be the initial point used in the loop). Within the loop, I first defined my recursive formula (which contains other arrays that are indexed; everything is switched to floating points) and it equates without trouble. Underneath this (still within the loop...

I was born on the fourth day of december in 1982 and in next 19 days i am the member of

mapleprimes for exactly 4 years ...

i read about the history of maple , so i noticed it is as old as me :) lucky fo me !

then i interested to know whether is there any special event in the maple lifesplan on my birth day ?

Bonjour,

Comment calculer avec Maple une intégrale première de omega:=(x^2-y*(x+y^2))*dx+x*(x+y^2)*dy.

Merci d'avance,

Gérard.

Hi,

     I have a set of first order, linear ODE's in matrix form, I was able to solve them with matrixDE for 4 equations (which were uncoupled), but I would like to up this to around 132+ equations if possible. When I tried 9 equations I got

 Error, (in collect/series) integer too large in context    

on my laptop and on my other computer it was very slow and I didn't wait for a solution. 

Should I try a numerical solution ...

Say I wanted to print out all values from 1 to 8 but excluding 3, how would I do that using a for loop?

For example, this just stops after 2:

for i to 8 while i <> 3 do
print(i);
end do ;

whereas I want it to skip 3 so going 1,2,4,5,6,7,8.

For what I'm actually doing, I need i to run over a range but excluding one value.

Thanks!

I am not sure if this is a general problem.  And I am considering the best way to evaluate the expression (Equation) when it contains variables which have been modified by using assume.   Here is a tiny test example:

restart;
assume(a>0,x>0);
int(int(x^2/y^2,y=1/x..x),x=1..a);S:=%:  
                        1  4   1   1  2

Greetings to all.

A recent post at math.stackexchange.com asked for good approximations to pi using the nine nonzero digits, the four arithmetic operations and exponentiation. The problem definition definitely suggests a computational solution, which is actually non-trivial because the search space of all legal mathematical expressions over the nine digits and with the aforementioned operations is so huge that it cannot possibly be searched exhaustively.

Hi,

I have the following code which solves a system od ode (3 ode) with constraint parameter. actually, this algorithm is time consuming and is not effective as I see that some people solve this odes with matlab in an efficient (qucik) way. So, I ask you if it is possible help me to improve the efficiency of the following code

thanks

restart:
eq1 := diff(u(eta), eta, eta)+diff(u(eta), eta)/ (eta+zet)+Gr*Pr*T(eta)-Nr*phi(eta)+sigma1;
eq2 := diff(T(eta), eta, eta)+diff(T(eta), eta)/(eta+zet)+Nb*diff(T(eta), eta)*diff(phi(eta), eta)+Nt*diff(T(eta), eta)^2-u(eta);
eq3 := diff(phi(eta), eta,eta)+diff(phi(eta), eta,eta)/(eta+zet)+ Nt/Nb*(diff(T(eta), eta, eta)+diff(T(eta), eta)/(eta+zet))-Le*u(eta);
zet:=0.1:
Nt:=0.05;
Nb:=0.05;
Le:=10;
Pr:=1;
Gr:=5;
Nr:=0.1;
Ree:=5;
#sigma:=2;



p:=proc(pp2) option remember; global res,F0,F1,F2;
if not type([pp2],list(numeric)) then return 'procname(_passed)' end if:
res := dsolve({subs(sigma1=pp2,eq1)=0,eq2=0,eq3=0,u(0)=0,u(1-zet)=0,phi(0)=0,phi(1-zet)=0,T(0)=0,T(1-zet)=0}, numeric,output=listprocedure);
F0,F1,F2:=op(subs(res,[u(eta),phi(eta),T(eta)]));
evalf((2/(1-zet^2))*Int(F0(eta)*(eta+zet),eta=0..1-zet))-Ree*Pr;
end proc;

fsolve(p(pp2)=0,pp2=(-80)..(80));   # I dont know what exactly this parameter has
#res := dsolve({eq1=0,eq2=0,eq3=0,u(0)=0,u(1-zet)=0,phi(0)=0,phi(1-zet)=0,T(0)=0,T(1-zet)=0}, numeric);
 

sigma1:=%;
                             
res := dsolve({eq1=0,eq2=0,eq3=0,u(0)=0,u(1-zet)=0,phi(0)=0,phi(1-zet)=0,T(0)=0,T(1-zet)=0}, numeric);
with(plots):
odeplot(res,[[eta,u(eta)],[eta,phi(eta)],[eta,T(eta)]],0..1-zet);

I have saved array calculated with Digits:=5000. Now I want to save it with Digits:=2500. I tried this

read "C:\\math\\lambda5000.mpl";

Digits := 2500;

LArr2500 := LArr5000;

save LArr2500, "C:\\math\\lambda2500.mpl"

But this don't work...