Hello!

I am calculating the temperature of a rod which has one end at the temperature T₁ and the other end at T₂ and it's evolution. We were already given the formula for the numeric calculation and after a short while I managed to obtain a small program that would calculate the temperature of each segment of the T(x,t) grid:

>restart: with(plots): nx:=20: tmax:=50: T1:=1: T2:=10: L:=1: k:=1: rho:=1: cp:=1: chi:=k/rho/cp: h:=L/(nx-1): t:=1e-3:
>for k from 0 to nx do T(k,0):=T1 od:
for w from 1 to tmax do
T(0,w):=T1: T(nx,w):=T2:
for q from 1 to nx-1 do
T(q,w):=T(q,w-1)+chi*t/h^2*(T(q+1,w-1)+T(q-1,w-1)-2*T(q,w-1));
od: od:

With L the Length of the rod, t and h the time and space increment [h=L/(nx-1), where nx is the number of intervals we divide the x-axis, although I'm not quite sure the '-1' should be there], chi a constant different for each rod and tmax total time we want to calculate. The formula from the 5th line was given to us, so in that part there is no mistake.

Up until here everything works perfectly fine.

Now I want to be able to draw this and here is where all the problems appear. I want to draw this in a 2D graph with position in the x-axis and time in the y-axis. I have tried "densityplot(T(x,y),x=0..nx,y=0..tmax)" which would seem to be the logical whay to continue this. As I understand it, this plot would draw an nx times tmax grid and colour the whole plpot black-white acording to the maximum and the minimum value (as shown in the maple help page of this plot).

However, when I do this a black square appears (or red if I add colorstyle=HUE). I have tried a lot of things and none seemed to work.

I would also like to be able to draw the isotherms on the plot but that is secondary.

I am pretty new to Maple. I have studied the most basic things but don't really understand the whole complexity of this program. Thanks a lot in advance and forgive my faulty english,

Enrique

Hi, currently im using maple 15

the coding did work but it is not the same with the answer
here, i attach the coding with the answer

coding:
derivation := proc (A, n)
local i, j, k, t, s1, s2, m, D, sols, eqns, Andre;
eqns := {};
D := matrix(n, n);
Andre := matrix(n, n);
for i to n-1 do
for j from i+1 to n do
for m to n do
s1 := sum(A[i, j, k]*D[m, k], k = 1 .. n);
s2 := sum(A[k, j, m]*D[k, i]+A[i, k, m]*D[k, j], k = 1 .. n);
eqns := `union`(eqns, {s1 = s2})
end do end do end do;
sols := [solve(eqns)];
t := nops(sols);
for i to t do
for j to n do
for k to n do
Andre[k, j] := subs(sols[i], D[k, j])
end do end do;
print(Andre)
end do end proc

the maple result showing:

> AS1 := array(sparse, 1 .. 2, 1 .. 2, 1 .. 2, [(1, 1, 2) = 1]);

> derivation(AS1, 2);
[D11 0]
[D21 D22]

> AS2 := array(sparse, 1 .. 2, 1 .. 2, 1 .. 2, [(1, 1, 1) = 1, (1, 2, 2) = 1]);
> derivation(AS2, 2);
[0 D12]
[D21 D22]

the maple should showing

> derivation(AS1, 2);
[D11 0]
[D21 2D11]

> AS2 := array(sparse, 1 .. 2, 1 .. 2, 1 .. 2, [(1, 1, 1) = 1, (1, 2, 2) = 1]);
> derivation(AS2, 2);
[0 0]
[D21 D22]

please help., thank you

how to field plot this system?

restart;
with(Physics[Vectors]);
with(DEtools);
with(VectorCalculus);
eq2 := ...;
eq3 := ...;
eq4 := ...;
with(DynamicSystems);
sys := DiffEquation([eq2 = t, eq3 = t], inputvariable = [b(t)], outputvariable = [a(t), c(t)]);
ts := .1;
in_t := t;
sol := Simulate(sys, [in_t]);

with(DEtools):
dfieldplot([...],[a(t),b(t),c(t)],t=−2..2,a=−1..2,b=−1..2,c=−1..2,arrows=SLIM,color=black,dirfield=[10,10]);

>assume(x>0, n>0):int(x^n*ln(x)^n,x);

I_Mariusz

Hello, I have a question.  I don't know why, but results of my calculations can't be saved in raschet document. This document excists, but there is no information in it! And I have an error with floating point format. How to solve that problems?

> restart;
> Digits := 5;
> NULL;
> NULL;
> NULL;
> NULL;
> NULL;
> ScS0 := P/(phi*f*kc*k0*deltad*Bm*etat);
> NULL;
> NULL;
> Sc := sqrt(ScS0);
> A := sqrt(Sc);
> B := A;
> NULL;
> mue := mu0*mur/(1+mur*dzet/lm);
> lm := 2*(LCA-A+(LC0+A))+dzet;
> NULL;
> LC0 := 3*A; LCA := .4*LC0; LD := .9*LC0;
> NULL;
> NULL;
> w1 := EE/(2*Pi*f*Bm*Sc);
> Lm := mue*w1^2*Sc/lm;
> ;
> I11 := sqrt((w2*Id/w1)^2+I0^2);
> ;
> NULL;
> ;
> h1 := sqrt(RAT*I11/deltad);
> ;
> h2 := sqrt(RAT*Id/deltad);
> NULL;
> A := .6;
> Ud := 35000;
> Id := 413;
> R := Ud^2/P;
> P := Ud*Id;
> P1 := P/eta;
> R1 := EE/I11;
> EE := 110000;
> I0 := EE/(2*Pi*f*Lm);
> w2 := w1*sqrt(P*R)/EE;
> mu0 := 4*Pi*10^(-7);
> mur := 1000;
> f := 50;
> k0 := .25;
> kc := .98;
> deltad := 0.3e7;
> Bm := 1.45;
> etat := .98;
> eta := .95;
> RAT := 1;
> dzet := 0.1e-3;
> phi := .5;
> W1 := evalf(w1);
324.55
> LLm := evalf(Lm);
13.407
> W2 := evalf(w2);
103.26
> evalf(lm);
7.2457
> evalf(LC0);
2.5877
> evalf(LCA);
1.0351
> Imax := evalf(I0);
26.117
> P1;
7
1.5215 10
> Rd := evalf(R);
84.746
> Bmm := evalf(mue*w1*I0/lm);
1.4500
> hâ := (.9*LC0*1000)/(w2+1)-4;

> evalf(hâ);

h￢
> Pred := Id/deltad;
> evalf(Pred);
0.00013767
> NULL;
> NULL;
> ll := hâ*(w2+1)+4*w2;
> NULL;
> a := am*nâ/nx;
> NULL;

> Pol := Vit*nâ;
> am := 5.1;
> am := 5.1;
> nâ := 4;
> evalf(a);
20.4
----
nx
> Vit := 35.19;
> evalf(Pol);
140.76
> plotnToka := Id/Pol;
> evalf(Id/Pol);
2.9341
> NULL;
> I1 := evalf(I11);
133.98
> NULL;
> evalf(mue);
0.0012395
> NULL;
> evalf(EE/I11);
821.02
> NULL;
> pr := "%";
"%"
> fd := fopen("C:\\Users\\Ñåìåí\\Desktop\\ÍÈÐ\\raschet4.ms", WRITE); fprintf(fd, "E=%g;Ud=%g;Imax=%g;P=%g;FR=%g;A=%g;B=%g;LC0=%g;LD=%g;LCA=%g;R=%g;BM=%g;", EE, Ud, Imax, P, f, A, B, LC0, LD, LCA, Rd, Bm); fprintf(fd, "\n %s P=%g;Id = %g;Bm=%g;I1=%g;Bmm=%g", pr, P, Id, Bm, I1, Bmm);
Error, (in fprintf) number expected for floating point format
Error, (in fprintf) number expected for floating point format
> fprintf(fd, "\n %s W1 = %g; W2 = %g; Lm=%g; Sc=%g; dzet=%g", pr, W1, W2, LLm, Sc, dzet);
Error, (in fprintf) file descriptor not in use
> fclose(fd);
Error, (in fclose) file descriptor not in use

I have a system of PDEs with 3 dependent variables (U, V, W) and 3 independent variables (x, y, t).

I need an explicit numerical solution, i.e., a table with the values of U, V and W, corresponding to several values of x, y and t.

Can anybody help me?

>tekssifer:="Qnuux*#Huh";

tekssifer:=Qnuux*#Huh

Hi, how i need to continue my command to get the size of tekssifer in bytes? 

Thank you~=]]

Before version 2016 Maple was incredibly good at evaluating an infinite power series and returning a simple function, e.g. 1/(3x+2).  Now version 2016 just returns the input sum expression with no change.  Is there some new command to get the old results?

Good day everyone, I would like to know how to work this out in a code on maple:
-I have some vectors (K(1),K(2),K(3) etc) similar to this:

K(1)=[A B C]

-I want to sort all of them by the value of C, but when I use the sort built in comand the program return a answer based on K index instead a sorting based on C.

Any ideas would be higly apreciated.

i want to solve these two coupled eqaut with finite boundary conditionsions. Can some one help me

eq1:=diff(f(eta),eta,eta,eta,eta)+2*(epsilon/(1+epsilon*theta(eta)))^2*diff(f(eta),eta,eta)*((diff(theta(eta),eta))^2)-(epsilon/(1+epsilon*theta(eta)))*(diff(theta(eta),eta,eta))*(diff(f(eta),eta,eta))=0;

eq2:=diff(theta(eta),eta,eta)+Pr*Re*f(eta)*diff(theta(eta),eta)=0;

Re:=1:Pr:=1:epsilon:=0.25:

bc:=f(1)=0,D(f)(-1)=0,D(f)(1)=1,D(f)(-1)=1,theta(-1)=0,theta(1)=0;

I have a column matrix with all the elements 1.

A:=Matrix(100, 1, 1):

I want to generate another matrix B exactly same as A but with one element changed and keeping all other elements to be same. Manually, I could do by following way:

A[1,1]:=1.1;
A;
B:=A;

But I have to do this with each of 100 elements of A. For instance, in step 1 I want only the first element changed into 1.1. In step 2 I want only the second element changed keeping all others to be 1, and go upto 100.

Could anyone give me an easy way to do this? I would like to appreciate your help in advance.

How can Maple solve that problem for me?

Given: a summation of one equation with its limits, equaling another summation with given limits, but NOt the equation. How do Maple be programmed to find that out? 

fx     [sum(x^(n)*y^(1-n), n=0..10, = sum(unknownequation),n=1..11)]   , find the unknown equation by maple?

Appreciating in advance,

Wanna ask that how to make maple program to select a random binary number in base 2.

For example, suppose that we have a value 11101100(8 bit which in base 2),then how to let Maple to select a binary number randomly and the binary bit of the random number always shorter than the previous then sum it together?

For example the program will select 1101101(7-bit) and sum it together(11101100+1101101=101011001,in base 2)

Can somebody help me thanks.

Hai everyone, wanna know that how to perform 2's complement method in maple 17?

For instance, 2's complement of 19 is 11101100(in base 2) in 8-bit binary representation.

Hello everyone,wanna ask that how to perform binary arithmetic(addition,subtraction,multiplication and division) in Maple.

For instances, how i need to perform:

1101+111=10100(all in base 2)

11000-1011=1101(all in base 2)

1011*1101=10001111(all in base 2)

10010011/1011=1101(all in base 2)

Kindly help,thanks.