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   So, no copyrights mean the materials/resources on this website can be freely copied/used by anyone?

I thought I could plot this by the graph below but I got an error...WHY is that?

with pointplot3d and 14,000 points when I enter symbol=point I get an empty plot.

Only when I set symbolsize=1 (a point) do I get points appearing in the graph.  Bug?

Hello everyone,

I came across an image/photo and thought, It will be fun to try it in maple.

Except plotting a few triangles and circles, I couldn't make it. 

Here is the image. 

Have a look please.

Cheers!

Bonjour,

Comment calculer, sous maple, le crochet de Poisson des deux fonctions suivantes :

f:=(x,y,u,v)->x*u+y*v;

g:=(x,y,u,v)->x*y^2+v^3;

Merci d'avance,

Gérard.

Dear Users

I have a problem for solving a system of linear equations that arise from collocation method for getting approximate solution of a coupled PDE and ODE in Food engineering problems.

When it reach to the fsolve command it takes long time!!!

I used maple 13.

If kindly is possible, please help me in this special case.

With kind regards,

Emran Tohidi.

> Restart;
print(`output redirected...`); # input placeholder
> h := 50; hm := 0.1e-3; rhodp := 1500; Y := 0.5e-1; T0 := 20; rhoair := 1.2041; Dair := 0.2e-8; DD := 0.85e-9; C := 3240; L := 0.4e-1; X0 := 1.5; V := .2; delta := 0.2e-2; Yair := 0.5e-1; nu := .2; Tair := 60; Hnu := 2400; rho := 1359; tt := 3;
%;
> N := 5; Digits := 20;
> X := sum(sum(a[m, n]*z^m*t^n, m = 0 .. N), n = 0 .. N); X := unapply(X, z, t); Xt := diff(X(z, t), `$`(t, 1)); Xt := unapply(Xt, z, t); Xz := diff(X(z, t), `$`(z, 1)); Xz := unapply(Xz, z, t); Xzz := diff(X(z, t), `$`(z, 2)); Xzz := unapply(Xzz, z, t); T := sum(b[n]*t^n, n = 0 .. (N+1)^2-1); T := unapply(T, t); Tt := diff(T(t), `$`(t, 1)); Tt := unapply(Tt, t); aw := exp(.914)*X(z, t)^.5639-.5*exp(1.828)*X(z, t)^(2*.5639); aw := unapply(aw, z, t); TT := 8.3036+3816.44*(1+T(t)/(46.13)+T(t)^2/46.13^2)/(46.13); TT := unapply(TT, t); pwv := 133.3*(1+TT(t)+(1/2)*TT(t)^2); pwv := unapply(pwv, t); Yi := .622*pwv(t)*aw(z, t)*(1+pwv(t)*aw(z, t)/rho+(pwv(t)*aw(z, t)/rho)^2)/rho; Yi := unapply(Yi, z, t);
%;
> S1 := {seq(seq(Xt(delta*i/N, tt*j/N)-DD*Xzz(delta*i/N, tt*j/N) = 0, i = 1 .. N-1), j = 1 .. N)};
> S2 := {seq(DD*rhodp*Xz(delta, tt*j/N)+hm*rhoair*Yi(delta, tt*j/N) = 0, j = 0 .. N)};
> S3 := {seq(Xz(0, tt*j/N) = 0, j = 0 .. N)};
> S4 := {seq(X(delta*i/N, 0) = 0, i = 1 .. N-1)};
> S5 := {seq(seq(rho*delta*C*Tt(tt*j/N)-h*(Tair-T(tt*j/N))+hm*Hnu*rhoair*(Yair-Yi(delta*i/N, tt*j/N)) = 0, j = 1 .. N), i = 0 .. N)};
print(`output redirected...`); # input placeholder
> S6 := {seq(rho*delta*C*Tt(0)-h*(Tair-T0)+hm*Hnu*rhoair*(Yair-Yi(delta*i/N, 0)) = 0, i = 0 .. N)};
%;
> SS := `union`(`union`(`union`(`union`(`union`(S1, S2), S3), S4), S5), S6);
> sol := fsolve(SS);

Hello, I have two plots:

Is it possible to display differene between these plots?

Bonjour,

Comment résoudre le système algébrique suivant :

f1:=(1+mu+nu)*(mu^2-2*mu*alpha+2*mu+2*mu*alpha*nu-2*alpha+1+alpha^2+2*alpha^2*nu+nu^2*alpha^2-2*nu*alpha)*(lambda*alpha^2-3*mu*alpha*nu^2+2*nu^2*mu-4*lambda*alpha*nu-mu^2*alpha*nu^2-lambda*alpha^3-nu*alpha+lambda*alpha-4*mu*alpha*nu+3*mu^2*nu-2*mu^3*alpha*nu+3*mu*nu-5*mu^2*alpha*nu+3*lambda*nu+mu^3*nu+3*nu^2*alpha^3*mu-5*lambda*mu^2*alpha*nu+3*lambda*alpha^3*mu-9*lambda*alpha*mu*nu+6*lambda*mu*nu+3*lambda*mu^2*nu-lambda+nu^2+nu+nu^3*alpha^3*mu-3*mu^2*alpha^2*nu-5*nu^2*alpha^2*mu-4*mu*alpha^2*nu-3*lambda*alpha^3*nu^2-3*lambda*alpha^3*nu-3*lambda*mu^2-nu^3*alpha+nu^2*mu^2+3*mu*alpha^3*nu+5*lambda*mu^2*alpha-5*lambda*mu^2*alpha^2+2*mu^2*alpha^3*nu-3*lambda*mu+mu^2*alpha^3*nu^2+alpha^3*mu+alpha^3*mu^2+3*lambda*alpha^3*nu^2*mu+6*lambda*alpha^3*mu*nu+5*lambda*alpha*nu^2*mu-9*lambda*alpha^2*mu*nu+5*lambda*mu^2*alpha^2*nu-5*lambda*alpha*nu^2-4*lambda*alpha^2*mu+mu*alpha*nu^3-2*nu^2*alpha+mu^3*alpha^2*nu-lambda*mu^3-mu^2*alpha^2*nu^2-lambda*alpha^3*nu^3-5*lambda*alpha^2*mu*nu^2+4*alpha^2*nu*lambda+5*lambda*alpha^2*nu^2+2*lambda*alpha^2*nu^3-2*nu^3*alpha^2*mu+2*lambda*mu^3*alpha-mu*alpha^2-2*mu^2*alpha^2-mu^3*alpha^2+4*lambda*mu*alpha);

f2:=(lambda+mu+nu)*(nu^2+2*mu*alpha*nu+mu^2*alpha^2+2*lambda*nu-2*lambda*alpha*nu-2*lambda*mu*alpha+2*lambda*alpha^2*mu+lambda^2*alpha^2-2*lambda^2*alpha+lambda^2)*(lambda^3*alpha^3*nu-5*mu*alpha*nu^2+3*nu^2*mu-mu^2*alpha*nu^2+lambda^3*mu-3*lambda*nu^2+mu^3*alpha*nu+5*mu^2*alpha*nu-3*lambda*mu^2*alpha*nu+lambda^2*mu^2-nu^3+mu*nu^3-3*lambda*alpha^3*mu^2-3*lambda^2*nu-9*lambda*alpha*mu*nu-lambda^3+6*lambda*mu*nu+2*lambda*mu^2*nu+3*lambda^2*mu-3*lambda^2*alpha^3*mu-5*mu^2*alpha^2*nu+5*nu^2*alpha^2*mu+mu^3*alpha^3*nu+3*lambda*nu^2*mu+2*nu^3*alpha+nu^2*mu^2-mu^3*alpha^3-5*lambda*mu^2*alpha+5*lambda*mu^2*alpha^2+3*lambda^2*nu*mu+3*mu^2*alpha^3*nu+mu^2*alpha^3*nu^2+2*lambda*alpha^3*nu^2*mu+6*lambda*alpha^3*mu*nu+3*lambda*alpha^3*mu^2*nu-5*lambda*alpha*nu^2*mu-9*lambda*alpha^2*mu*nu-5*lambda*mu^2*alpha^2*nu+5*lambda*alpha*nu^2-lambda^3*alpha*mu-4*lambda^2*alpha^2*nu-2*mu*alpha*nu^3+3*lambda^2*alpha^3*mu*nu-2*lambda^2*alpha*mu^2-4*lambda^2*alpha*mu-2*mu^3*alpha^2*nu-mu^2*alpha^2*nu^2+3*lambda^2*alpha^3*nu+lambda^2*alpha^3*nu^2-3*lambda*alpha^2*mu*nu^2+lambda^3*alpha^2+lambda^3*alpha-4*lambda^2*alpha^2*mu*nu-4*lambda^2*alpha*nu*mu-5*lambda*alpha^2*nu^2+4*lambda^2*alpha*nu-lambda*alpha^2*nu^3+nu^3*alpha^2*mu-lambda*mu^3*alpha-lambda^3*alpha^3+2*mu^3*alpha^2+4*lambda^2*alpha^2*mu-lambda^3*alpha^2*nu-2*lambda^2*alpha^2*nu^2);

f3:=(1+nu+lambda)*(nu^2*alpha^2-2*nu^2*alpha+nu^2-2*lambda*alpha*nu+2*lambda*nu-2*nu*alpha+2*alpha^2*nu+lambda^2+2*lambda*alpha+alpha^2)*(2*lambda*alpha^2+4*mu*alpha*nu^2-3*nu^2*mu+3*lambda*alpha*nu-lambda*alpha^3+lambda^3*mu+nu*alpha-3*lambda*nu^2-lambda*alpha+5*mu*alpha*nu-2*lambda*nu+3*nu^2*alpha^3*mu-nu^3+mu*nu^3-3*lambda*alpha^3*mu-3*lambda^2*nu+9*lambda*alpha*mu*nu-lambda^3-6*lambda*mu*nu-3*lambda^2*mu-nu^2+nu^3*alpha^3*mu-4*nu^2*alpha^2*mu-5*mu*alpha^2*nu-3*lambda*alpha^3*nu^2-3*lambda*alpha^3*nu+3*lambda*nu^2*mu+nu^3*alpha-lambda^2+3*mu*alpha^3*nu+3*lambda^2*nu*mu+alpha^3*mu-3*lambda*alpha^3*nu^2*mu-6*lambda*alpha^3*mu*nu-4*lambda*alpha*nu^2*mu+9*lambda*alpha^2*mu*nu+4*lambda*alpha*nu^2-2*lambda^3*alpha*mu+3*lambda^2*alpha^2*nu+5*lambda*alpha^2*mu-mu*alpha*nu^3+5*lambda^2*alpha*mu-lambda^2*alpha^3+2*nu^2*alpha+lambda^2*alpha^2-2*lambda^2*alpha^3*nu-lambda^2*alpha^3*nu^2-lambda*alpha^3*nu^3+4*lambda*alpha^2*mu*nu^2-lambda^3*alpha^2+2*lambda^3*alpha+5*alpha^2*nu*lambda+5*lambda^2*alpha^2*mu*nu-5*lambda^2*alpha*nu*mu+lambda^2*alpha+4*lambda*alpha^2*nu^2+5*lambda^2*alpha*nu+lambda*alpha^2*nu^3-nu^3*alpha^2*mu-2*mu*alpha^2-5*lambda^2*alpha^2*mu+lambda^3*alpha^2*nu+2*lambda^2*alpha^2*nu^2-5*lambda*mu*alpha);

f4:=(1+mu+lambda)*(mu^2*alpha^2-2*mu^2*alpha+mu^2-2*lambda*mu*alpha+2*mu+2*lambda*alpha^2*mu-2*mu*alpha+lambda^2*alpha^2+2*lambda*alpha+1)*(lambda^3*alpha^3*nu-lambda*alpha^2+5*lambda*alpha*nu-2*nu*alpha+2*lambda*alpha-5*mu*alpha*nu+3*mu^2*nu-mu^3*alpha*nu+3*mu*nu-4*mu^2*alpha*nu-3*lambda*nu+mu^3*nu+4*lambda*mu^2*alpha*nu-lambda^2*mu^2-3*lambda*alpha^3*mu^2-2*lambda*alpha^3*mu+9*lambda*alpha*mu*nu-6*lambda*mu*nu-3*lambda*mu^2*nu-2*lambda^2*mu-lambda+nu-3*lambda^2*alpha^3*mu+4*mu^2*alpha^2*nu+5*mu*alpha^2*nu+mu^3*alpha^3*nu-3*lambda*mu^2-lambda^2-mu^3*alpha^3+4*lambda*mu^2*alpha+4*lambda*mu^2*alpha^2-3*mu^2*alpha^3*nu-3*lambda*mu-alpha^3*mu^2-6*lambda*alpha^3*mu*nu+3*lambda*alpha^3*mu^2*nu+9*lambda*alpha^2*mu*nu-4*lambda*mu^2*alpha^2*nu+lambda^3*alpha*mu+5*lambda^2*alpha^2*nu+3*lambda*alpha^2*mu+3*lambda^2*alpha^3*mu*nu+2*lambda^2*alpha*mu^2+3*lambda^2*alpha*mu-lambda^2*alpha^3-mu^3*alpha^2*nu-lambda*mu^3+lambda^2*alpha^2-3*lambda^2*alpha^3*nu+2*lambda^3*alpha^2-lambda^3*alpha-5*alpha^2*nu*lambda-5*lambda^2*alpha^2*mu*nu+5*lambda^2*alpha*nu*mu+lambda^2*alpha-5*lambda^2*alpha*nu+lambda*mu^3*alpha-lambda^3*alpha^3+mu*alpha^2+2*mu^2*alpha^2+mu^3*alpha^2+5*lambda^2*alpha^2*mu-2*lambda^3*alpha^2*nu+5*lambda*mu*alpha);

Merci d'avance,

Gérard.

I don't understand how to create better parameters. Why is the graph not flush with the image (it appears that the graph is a set of points and NOT lines)

From the manual: coeffs - extract all coefficients of a multivariate polynomial. Is there a way of doing the reverse (giving the coefficients, obtain the multivariate polynomial) ? For univariate polynomials I know that the answer is yes because  PolynomialTools[FromCoefficientList] - return a univariate polynomial from list of coefficients. But what about multivariate polynomials?

ACP.mw

hi all

trying to modify some kitonum code to get the smallest solution, d=3,515,820, but i have problem....

http://en.wikipedia.org/wiki/Archimedes'_cattle_problem

Hello,
I'm working on coupled differential equation.
The first system is : 
y₁''+y₁'+y₁=q₁
q₁''+e(q₁²-1)q₁'+q₁=y₁"

And the second one : 
y₂''+y₂'+y₂=q₂
q₂''(t)+e(q₂²-1)q₂'(t)+q₂(t) = y₂"+f(P) q₁(t-tau)

This is a parametric system, f(P) and tau(P) are given function of the parameters P.
e is a constant

I have solved the first system with dsolve (using numeric option).
But when I try to solve the second one (with dsolve, numeric, setting P as a parameter), maple returns an error : 

"Error, (in dsolve/numeric/process_input) input system must be an ODE system, got independent variables {t, t-1}"

I think Maple doesn't like " q1(t-tau)".
I have tried to create a new function q where :
q(t)=q1(t-tau)
But Maple returns the same error.

How can I fix it ?

Thanks for reading

EDIT : I have read there is no function in maple that solve delay differential equation.
But this is not a true DDE because q₂ has no effect on q₁. 
So I hope there is a way to "fool" maple and still use dsolve.

EDIT 2 :
I have found how to make it works.
I was using dsolve with the option compile (which increase (a lot) the efficiency of computation).
I delete this option and that's working.
Nevertheless, without the option compile, the computation is very very slow.
MapleHelp recommands to combine the 2 systems for more efficiency. But, when I combine, maple return the previous error.
How can I make it quicker ?

Here is the code : 

test_2_cylindre_sans_compile.mw 

hello,

i have unistalled maple, now i have to give the license server name and the purchase code to reactivate it, how can i do?? where i can find them?

someone can help me?!

hello guys

i have a 2-sphere metric (ds^2=dθ^2+sinθ^2 dφ^2) , how to calculate R^abcd R_abcd . 

thank you very much

Hi dear users:

i will plot the equation below abs(y) in terms of x,(note:abs(y) and x is real values),can every body help me?

eq:

-32.46753247/(Pi*x^2)+1.053598444*10^8*Pi^2*y/x^2-5.342210338*10^14*Pi^2*y*(2.574000000*10^8*Pi^2-.7700000000*x^2)/((-3.904240733*10^6*x^2+1.305131902*10^15*Pi^2-159.8797200*Pi^2*x^2+2.672275320*10^10*Pi^4+2.391363333*10^(-7)*x^4)*x^2)+1.504285714*10^9*Pi^4*y^3/x^2 = y