Hi Mapleprimes,

We know that '' rsolve '' is a recurrence equation solver.  It is more than an expression simplifier.

Congratulations to the Maple computer algebra team for creating such a great computer tool.  simply want to know more.

rsolve_on_May_16_2017.pdf

Surely there are many steps to determine the values to place.

Regards,

Matt

I recently encontered a very strange result.

Lets define the procedure:

Fg := proc(x0,y0)
if (x0>=0)and(x0<=3) and (y0<=x0+2) and (y0>=x0-1) and (y0>=0) and (y0 <=3) then
return y0*(3-y0)*x0*(3-x0)*(x0+2-y0)*(y0-x0+1);
else
return 0;
end if:
end proc:

The plot looks like needed:

plot3d('Fg'(x,y), x=0..3, y=0..3);

But integration returns weird result:

evalf(Int('Fg'(x,y), [x=0..1, y=0..2.1]));

7.888753239

evalf(Int('Fg'(x,y), [x=0..1, y=0..2.2]));

Error, (in evalf/int) when calling 'Fg'. Received: 'cannot determine if this expression is true or false: 0 <= x and x <= 3 and y <= x+2 and x-1 <= y and 0 <= y and y <= 3'

hi...i have a problem with pdsolve this equations?

please help me.

thanks

mt.mw

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/mt.mw .
 

Download mt.mw

I have a expression p:=C*A+A, when i type this to maple, maple display into p:=A*C+A because commutative property of multiplication

but I dont want to do like that. How can I display into p:=C*A+A?

Hi Guys,

got my last Problem solved :) Now i do have a new one...

restart; with(RealDomain); with(CodeGeneration); with(ExcelTools); with(plots);
dx1:=133;
dy1:=132;

n := 1; 
for i to 256 do 
for j to 256 do 
r := evalf(sqrt((i-dx1)^2+(j-dy1)^2)); 
Ints := R0[i, j]; 
IntsR[n] := [r, Ints]; 
n := n+1 
end do; 
end do; 
IntsR := [seq(IntsR[i], i = 1 .. n-1)]

The list IntsR consists of unsorted values doublets. Now it would be nice to get some sort of mean value of my Ints over r.  Didnt really find a solution for it until now... do you have any hint?

Hi, i'm working with some spectral acceleration data and i'm having troubles with a 'local' command on a Newmark method code i found on the internet. I'm not a maple expert so i wish someone could help me. i'm ussing maple 2015. Greetings

Newmark=proc(z0,u0,F0);  local beta,  dt, c, kg,a,b, N, i, dF, dz, du, dw, T, m, k ;        dt:=0.01;    T:=4;    N:=T/(dt);    gam:=0.5;    beta:=0.25;      m:=0.320;    k:=435;    c:=2;   z(0):=z0;   u(0):=u0;   F(0):=F0;   w(0):=(1/(m))*(F0-k*z0-c*u0);        t=vector(i,1);    t[1,1]=0;      for i from 2 to N do :  t(i,1)=t(i-1,1)+dt:  end do:           kg:=k+(gam*c)/(beta*dt)+m/(beta*dt*dt);    a:=m/(beta*dt)+(gam*c)/(beta);    b:=  (0.5*m)/(beta)+dt*((0.5*gam)/(beta)-1)*c;       for i from 2 to N do  dF(i):=diff(F,t)+a*u(i)+b*w(i);    dz(i):=(dF(i))/(kg);    du(i):=((gam*dz(i))/(beta*dt))-((gam*u(i-1))/(beta))+dt*(1-gam/(2*beta))*w(i-1);    dw(i):=((du(i))/(beta*dt*dt))-((u(i-1))/(beta*dt))-((w(i-1))/(2*beta));     z(i+1)=dz(i)+z(i);    u(i+1):=du(i)+u(i);    w(i+1):=dw(i)+w(i);     od;       plot([z(i), u(i), w(i)],x=0..50,y=-50..50);       end;

Consider substutition with use of a function:

subs(F(x,y)=f(x)+g(y), F(x,y));

As expected, Maple returns the proper answer:

f(x)+g(y)

But 

subs(F(x,y)=f(x)+g(y), F(x,x));

returns 

F(x,x)

How to force Maple recognize F as a function, in order to obtain

f(x)+g(x)

in return?

The functions algsubs, applyrule work in the same way.

Good day everyone,

I'm trying to convert a series solution back to its original function but its given me "Error, (in rsolve/linindex) invalid subscript selector".

Anyone with useful informations please.

Attached is the series below

theta := convert(a-(1/2)*beta*a^2*y^2+(1/12)*beta^2*a^3*y^4-(1/72)*beta^3*a^4*y^6+(1/504)*beta^4*a^5*y^8-(5/18144)*beta^5*a^6*y^10+(1/27216)*beta^6*a^7*y^12-(95/19813248)*beta^7*a^8*y^14+O(y^16), polynom);
     1       2  2   1      2  3  4   1      3  4  6
 a - - beta a  y  + -- beta  a  y  - -- beta  a  y 
     2              12               72            

       1      4  5  8     5       5  6  10     1       6  7  12
    + --- beta  a  y  - ----- beta  a  y   + ----- beta  a  y  
      504               18144                27216             

         95        7  8  14
    - -------- beta  a  y  
      19813248             
L := [seq(coeff(theta, y, n), n = 0 .. 14)];
  [        1       2     1      2  3       1      3  4     
  [a, 0, - - beta a , 0, -- beta  a , 0, - -- beta  a , 0, 
  [        2             12                72              

     1      4  5         5       5  6       1       6  7     
    --- beta  a , 0, - ----- beta  a , 0, ----- beta  a , 0, 
    504                18144              27216              

         95        7  8]
    - -------- beta  a ]
      19813248         ]
with(gfun);
rec := listtorec(L, u(n));
[ //      2     2  3         2     2  2          2     2  \        
[{ \2151 a  beta  n  - 1434 a  beta  n  - 30592 a  beta  n/ u(n) + 
[ \                                                                

  /             3                  2                  
  \2476 a beta n  - 137904 a beta n  + 207248 a beta n

                  \         
   + 424320 a beta/ u(n + 2)

     /         3           2                      \           
   + \-153660 n  - 322920 n  + 1803360 n + 2545920/ u(n + 4), 

                               1       2          \      ]
  u(0) = a, u(1) = 0, u(2) = - - beta a , u(3) = 0 }, ogf]
                               2                  /      ]

rsolve(rec[1], u);
      / //      2     2  3         2     2  2          2     2  \ 
rsolve|{ \2151 a  beta  n  - 1434 a  beta  n  - 30592 a  beta  n/ 
      \ \                                                         

         /             3                  2                  
  u(n) + \2476 a beta n  - 137904 a beta n  + 207248 a beta n

                  \         
   + 424320 a beta/ u(n + 2)

     /         3           2                      \           
   + \-153660 n  - 322920 n  + 1803360 n + 2545920/ u(n + 4), 

                               1       2          \    \
  u(0) = a, u(1) = 0, u(2) = - - beta a , u(3) = 0 }, u|
                               2                  /    /
sum(%*y^n, n = 0 .. infinity);
Error, (in rsolve/linindex) invalid subscript selector

thanx

My subsection have so many lines of codes, sometimes I want to disable one subsection, is there simple way to disable one subsection? it is tedious to set # at each lines of the subsection.

Is there any way to say maple dont open specified subsection during the running?

I have a system of ODE that I need to get an exact solution to. How can I do this using Maple? I tried doing it but error pops out.

Thanks

I need help with these two questions. anything is helpful

I plotted number of functions y=y(x) with different parameter aa for given value of tau (see the code below) 

restart;
R0:=gamma+2*ln(2)+Re(Psi(1/2+(1+I)*tanh((1+I)*x)/((tau+0.25e-1*a)*y)))+ln(y);
tau := 9.975;
with(plots);
implicitplot({seq(R0, a = 1 .. 50)}, x = 0 .. 5, y = 0 .. 1, numpoints = 1000);

Thanks in a advance.

Hi, I try to create quizes in Maple 2016, but I don't know how to hide the Maple commands. Is it possible?

I'd like my students to see only 

when they access the quiz. Any help will be highly appreciated. Thank you.
 

I can not understand why the following statement works perfectly:
with (plots);
P1: = plot (f (x), x = xmin .. xmax, y = ymin .. ymax, color = "green");
P2: = plot (orddir, x = xmin .. xmax, y = ymin .. ymax, color = "blue");

Plots [display] (plottools [line] ([ascf, ymin], [ascf, 10]), color = red;
Plot ([5, y, y = 0 .. 10]);
P3: = implicit plot (x = ascf, x = xmin .. xmax, y = ymin .. ymax, color = red, linestyle = 3, thickness = 2);
P4: = plot (points, x = xmin .. xmax, y = ymin .. ymax, style = point, symbol = circle, symbolsize = 20, color = "black");
P5: = plot (h, x = xmin .. xmax, y = ymin .. ymax, color = "yellow");
Display ({p1, p2, p3, p4, p5}, axes = normal, scaling = unconstrained, title = "Parallel, vertice, focus, direction and axis of symmetry", gridlines = true);

While in the following
Points: = [F, V, A, B];
with (plots):
P1: = plot (f (x), x = xmin .. xmax, y = ymin .. ymax, color = "green");
P2: = plot (yd, x = xmin .. xmax, y = ymin .. ymax, color = "blue");
P3: = implicitplot (x = xv, x = xmin .. xmax, y = ymin .. ymax, color = red, linestyle = 3, thickness = 2);
P4: = plot (points, x = xmin .. xmax, y = ymin .. ymax, style = point, symbol = circle, symbolsize = 20, color = "black");

Do (% Plot0 = display ({p1, p2, p3, p4}, axes = normal, scaling = unconstrained, title = "Parallel, vertices, focus, direction and axis of symmetry", gridlines = true));

P4 does not print anything. In thanking you for the kind attention, I cordially greet you. Carmine Marotta ..

Download TravelingSalesman-test.mw