## Error, number of indices exceeds rank...

Hello.

I have been trying to create a code to solve a structure by using FEM, but I keep getting an error that stops me from moving on.

Everytime I run my code, Maple gives me the error in the Title of my question:
"Error, number of indices exceeds rank"

Unfortunately I can't find any help in Maplesoft support for such error, and I need immediate help for that.

Can someone help me with that? Should I post my entire code?

Thanks!

## solve trigonometric system of equation with condit...

I want to solve this equation with assumptions!!!

restart;
assume(d::real, d>0):
assume(a::real, -0.01 < a, a < 0):
sys:={-800*Pi*a*cos(6.557377048*Pi*(3.470797713+d))/(a+1)^3 = -.9396060697, 800*Pi*a*sin(6.557377048*Pi*(3.470797713+d))/(a+1)^3 = -.3238482794};
solve(sys, {a,d},useassumptions=true, AllSolutions=true);

one of the solutions has true "a" but "d" is wrong, I want one true solution!

## Eigenvalues. Mechanical problem...

I solve a mechanical exercise but i had a problem.

I know M (mass) and K (stifness) matrices (4x4).

I want to solve the (λ2M+K)v=0  eigenvalue problem, where λ are the eigenvalues and v eigenvectors.

How can i solve this problem.  I tried with the Eigenvectors() command but it didn't give the right solution.

The Eigenvalues are okay, but the eigenvectors not

K := Matrix([[4*10^7,-1.50*10^7,2*10^7,0],[-1.50*10^7,1.50*10^7,0,1.50*10^7],[2*10^7,0,8*10^7,2*10^7],[0,1.50*10^7,2*10^7,4*10^7]]);

M:=Matrix([[121.90,99.048,-91.429,0],[99.048,594.29,0,-99.048],[-91.429,0,243.81,-91.429],[0,-99.048,-91.429,121.90]]);

w1,w2:=Eigenvectors(K,M);

Acoording with the book the right eigenvectors(shape mode) are:

[0.013 991,  0.034 233,  0.073 683,  0.090 573]
[0.035 637, 0, -0.032 213, 0]
[0 ,-0.034 233, 0, 0.090 573]
[-0.013 991, 0.034 233, -0.073 683, 0.090 573]

Thank you

## Kernel connection lost...

Regarding my recent question http://www.mapleprimes.com/questions/221909-How-To-Extract-Data-From-Implicit-Function I would like to share an interesting observation. Here the code of the program:

```restart;
R0 := ln(y)+Re(Psi(1/2+(2*(p^2+(1/2)*sqrt(2*I+4*ksi_fs^2*p^2)*tanh(sqrt(2*I+4*ksi_fs^2*p^2)*x)/(tau+0.5e-2*a)))/y))+gamma+2*ln(2)
tau:= 10.000:ksi_fs:=10:p:=0.037:
R0p:= unapply(R0, [a,x]):
R0f:= proc(a,x)
local r:= fsolve(R0p(a,x), y= 0..1);
`if`(r::float, r, Float(undefined))
end proc:
M:= Matrix(
(100,100),
(i,j)-> R0f(i, 1 + (j-1)*(0.5-0)/(100-1)),
datatype= float[8]
);```

After approximately 2 hours of calculations I get a message window

But I repeat this calculations on another computer with the same Windows 7 64 bit and Maple 17 I don't get such error and I obtain desired data.

So can Maple be sensitive to the hardware?

## How to numerically solve differential equation?...

I'm trying to numerically solve the differential equation: y' = -2xy + 1. Naturally, I come across the non-elementary integral of e^(x^2). By hand, I used a 2nd degree MacLaurin polynomial to get y = xe^(-x^2) + x^3/3e^(-x^2)+x^3/6e(-x^2).

How do I use Maple to numerically solve this, with step sizes of h=0.1 and h=0.05 and plot them?

## How do i write a "if...then" function in Maple?...

Hi all, I'm using text box and push button to create my user interface for my system. I  wish to use a if..then function to check some condition, if the condition is true then do statement and print out in the text box. When is key coding in the push button and click the push button, then if ...then function not working and the result that not suitable for the condition also have been printed out in text box.So,can someone help my to solve the problem?

Here in the coding i did

use DocumentTools in

Do (C = %txtC);
Do (p = %txtpk1);
Do (q = %txtpk2);
Do (d = %txtpk3);
Do (A1 = %txtA1);
Do (A2 = %txtA2);
Do (w = `mod`((C*d), A2));
Do (mp = `mod`(w^((p+1)*(1/4)), p));
Do (mq = `mod`(w^((q+1)*(1/4)), q));
Do (hl = `mod`((mp-mq)/p, q));
Do (h2 = `mod`((-mp-mq)/p, q));
Do (m1 = mp+(hl*p));
Do (m2 = mp+(h2*p));
Do (m3 = (p*q)-m1);
Do (m4 = (p*q)-m2);
if m1 <= 2^(2*k-1) then t1 := (C+(-A1*(m1^2)))/A2 end if;
Do (t1);
if m2 <= 2^(2*k-1) then t2 := (C+(-A1*(m2^2)))/A2 end if;
Do (t2);
if m3 <= 2^(2*k-1) then t3 := (C+(-A1*(m3^2)))/A2 end if;
Do (t3);
if m4 <= 2^(2*k-1) then t4 := (C+(-A1*(m4^2)))/A2 end if;
Do (t4);

Do (%txtw = w);
Do (%txtm1 = m1);
Do (%txtm2 = m2);
Do (%txtm3 = m3);
Do (%txtm4 = m4);
Do (%txtt1 = t1);
Do (%txtt2 = t2);
Do (%txtt3 = t3);
Do (%txtt4 = t4);
end use;

Thabk you.

## Creating a list of Matrices...

I need to create a list of matrices.

with(LinearAlgebra):
interface(rtablesize=50);
E:=[E1,E2,E3]:
P:=[0,1,2]:
N:=3:
B:=[1,2,3]:
for b from 1 to 12 by 5 do
B:=(i,j)->
if i=b+P[a] and j=b+P[a] then E[a]
elif i=b+P[a] and j=b+N+2+P[a] then -E[a]
elif i=b+P[a]+N+2 and j=b+P[a] then -E[a]
elif i=b+P[a]+N+2 and j=b+P[a]+N+2 then E[a]
else 0:
end if:
end do;
H:=[seq(B[b],b=1..12,5)];

It isn't indexing the first and second variable, only the last one was indexed.

## Error, (in plot3d) bad range arguments:...

Can't understand what's wrond. This text from my academic books but it doesn't work on practice. Help please

plot3d(polygons([[0, 0, 0], [1, 0, 0], [1, 0, 0], [0, 1, 0]], [[0, 0, 0], [0, 1, 0], [0, 1, 1], [0, 0, 1]], [[1, 0, 0], [1, 1, 0], [1, 1, 1], [1, 0, 1]], [[0, 0, 0], [1, 0, 0], [1, 0, 1], [0, 0, 1]], [[0, 1, 0], [1, 1, 0], [1, 1, 1], [0, 1, 1]], [[0, 0, 1], [1, 0, 1], [1, 1, 1], [0, 1, 1]]), light(0, 0, 0.0, 0.7, 0.0), light(100, 45, 0.7, 0.0, 0.0), light(100, -45, 0.0, 0.0, 0.7), ambientlight(.4, .4, .4), title(cube), style(patch), color(zhue));

Error, (in plot3d) bad range arguments: light(0, 0, 0., .7, 0.), light(100, 45, .7, 0., 0.)

## Display Expression...

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?

## How can I get an Exact solution for system of ODE ...

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

## How to extract data from implicit function with a ...

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);
``````

## How to label axes in Maple...

Pls how can I label my vertical axis in such a way that the label will be written vertically e.g "proportions of Susceptible"

## New to Maple. Trying to sovle 3rd order PDE system...

Hi I am new to Maple. I have 2 question:

1)I tried to run the following but I get this error as shown.pde1 is the PDE system. IBC, or you can refer bc1 to bc5 are the boundary condition given.

2)My bc4 & bc5 is suppose to be approaching 0 when y approch infinity  which is why I just put y to be equal to a large value while bc4 and bc5 equal 0. Do Maple have a function to use the approach method?

restart; with(PDEtools):

pde1 := [(x*y+1)*(diff(f(x, y), y, y, y))+(x+f(x, y))*(diff(f(x, y), y, y))-(diff(f(x, y), y))^2+g(x, y) = 0, (x*y+1)*(diff(g(x, y), y, y))+(x+f(x, y))*(diff(g(x, y), y))-(diff(f(x, y), y))*g(x, y) = 0];

IBC := [eval(f(x, y), y = 0) = 0, eval((D[2](f))(x, y), y = 0) = 0, eval(g(x, y), y = 0) = 0, eval((D[2](f))(x, y), y = 10000000000) = 0, eval(g(x, y), y = 10000000000) = 0];

bc1 := eval(f(x, y), y = 0) = 0

bc2 := eval((D[2](f))(x, y), y = 0) = 0

bc3 := eval(g(x, y), y = 0) = 0

bc4 := eval((D[2](f))(x, y), y = 10^10) = 0

bc5 := eval(g(x, y), y = 10^10) = 0

sol1 := pdsolve(pde1, [IBC], numeric, [f(x, y), g(x, y)], 'spacestep' = 0.1e-2, 'indepvars' = [x, y])

Error, (in pdsolve/numeric/process_IBCs) invalid initial/boundary condition: [f(x, 0) = 0, (D[2](f))(x, 0) = 0, g(x, 0) = 0, (D[2](f))(x, 1000000000000) = 0, g(x, 1000000000000) = 0]

## How can I increase the 1000000 limit of output...

Please is it possible to increase the 1000000 limit of output? I tried doing some computation in form of power series for S10 but I got the message "1000000 limit of output exceeced". How can I resolve this?