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 ...

> with(PDEtools):
> declare(y(x), prime=x):
> ode := diff(diff(y(x),x),x)*diff(y(x),x)*y(x)*f(x)-2*diff(y(x),x)^3*x^6> + 2*diff(y(x),x)^2*y(x)*diff(g(x),x) + y(x)^5; 
 diff(ode,diff(y(x),x));
Error, invalid input: diff received diff(y(x),x), which is not valid for its 2nd argument

 i want to make deravatition with respect to the first deravatives,what should i do? 

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

Hello,

I've made multiple graphs, and plotted them with the command 'display'. I also put a legend to every plot I made.

But now the legend which is showed by using 'display' is given randomly. So I put in different heights from say 200 mm to 1000 mm, with 100 mm spaces in between. The legend gives me randomly all the heights: like 200, 400, 100, 300, 700...etc. Is there a way to organise or order the legend? So that I can say I want the legend to start at 200 mm and end it at 1000 mm. So a kind of an ascending height legend. That is way more pleasant to the reader, obviously.

Greetings.
Frank

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);

Hi,

I'd like to change the font size in my MapleSim plots, especially when I resize the plot to take up the whole screen.  I know how to set the line thickness of the plot lines, but I can't seem to find an option for setting the font size in the legends, titles and axes.

Also, is there a way to change the default font and line width?  

thanks!

James

Aslam-u-Alikum. How are you? I want to construct an operators to find the derivative and integration of fractional order please help me i am so tens.Jam.mw

Hi,

I have a list of sets eg. L:=[{a},{b,c},{d,a,f},{b,d}] and I'm having problems doing operations on it. 

I want to be able to take the first element (a here), look for the next occurrence of it and return what is in the set with it (here d and f).

However I can't seem to use Search or Occurrences as they consider the sets themselves to be the elements. For instance Search(a, L) returns 0. 

What can I do?

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...

Hi,

I have a problem solving two equations with trigonometric functions. They are as follows:

eq1:= 9180pi - 16295.070arccos(-1.0 + 0.001356852103xu) + 22.1100sin(-1.0pi + 1.0arccos(-1.0 + 0.001356852103xu))(737.0-xu)+7115.0700arccos(-1.513347022 + 0.002053388090xu) - 14.6100sin(-1.0pi + 1.0arccos(-1.513347022 + 0.002053388090xu))(737.0-xu) + (0.1050As(xu-125)/(1349-xu)) - 0.1050As = 1688

eq2:= 9180pi- 16295.070arccos(-1.0 + 0.001356852103xu) + 22.1100sin...

t0 := arccosh(lambda/(s*(1-lambda)))

f := int(sqrt(lambda-s*cosh(t)/(1+s*cosh(t))), t = -t0 .. t0)

s := 1/10

with(Student[Calculus1])

g := f-Pi*(0+1/2)

Roots(g, lambda = 0 .. 1, numeric)

Why does maple say:

Error, (in mod/Expand) too many levels of recursion?

r(t) = RootOf(Int(_a/sqrt(-4*_a^4+5*_a^2-1), _a = 1 .. _Z)+t), r(t) = RootOf(Int(_a/sqrt(-4*_a^4+5*_a^2-1), _a = _Z .. 1)+t), r(t) = RootOf(Int(_a/sqrt(-4*_a^4+13*_a^2-9), _a = 1 .. _Z)+t), r(t) = RootOf(Int(_a/sqrt(-4*_a^4+13*_a^2-9), _a = _Z .. 1)+t)

ist my result of an ODE

g := dsolve([oder, r(0) = 1, (D(r))(0) = 0])

oder := diff(r(t), t, t) = 4*sqrt(1-(diff(r(t), t))^2)+(1-(diff(r(t), t))^2)/r(t)

Now usually maple gives me one solution, so I can just plot with

Hi all,

This might be more a mathematical problem than a Maple problem, but still maybe somebody could help me out.

I am trying to solve the differential equation of an Euler-Bernoulli beam with an distributed load (q1) and a varying axial force (N(x)). The following equation applies: