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## How to Graph Overlaying Plots With No Errors?...

I am trying to plot some graphs for a differential equations class. I need to plot two equations (soln1a, soln1b1) in one graph, with the two curves overlayed on each other. I am trying to plot them on a graph named "gr1c". The error I get says "Error, (in plots/multiple) empty plot". Clicking on the error results in a webpage saying that "There is no help page available for this error".

When I plot each equation separately, there are no errors. The graphing command that works for soln1a is

gr1a:=plot(rhs(soln1a),dom1,color=blue);

and the graphing command that works for soln1b1 is

gr1b1:=plot(rhs(soln1b_1),dom1,color=purple);

My code is as follows. I would greatly appreciate any help ASAP to remove the error. Thank you!

with(plots):with(DEtools):

K:=9;
deG:=diff(theta(t),t,t) + mu*diff(theta(t),t)+K*sin(theta(t))= 0;
deL:=diff(theta(t),t,t) + mu*diff(theta(t),t)+K*theta(t)= 0;
Iv:=theta(0)=0.75, D(theta)(0)=2.0;
dom1:=t=0..10;
soln1a:=dsolve({eval(deL,mu=0),Iv});

soln1b_1:=dsolve({eval(deL,mu=1),Iv});

gr1c:=multiple(plot[soln1a,soln1b1],dom1,color=[blue,purple]);

## How to fix the behaviour of the LinearAlgebra[Eige...

In Maple18.02:

Hso := Matrix(8, {(1, 4) = -x, (1, 6) = I*x, (2, 3) = x, (2, 5) = I*x, (3, 2) = x, (3, 5) = -I*z, (3, 8) = y, (4, 1) = -x, (4, 6) = I*z, (4, 7) = -y, (5, 2) = -I*x, (5, 3) = I*z, (5, 8) = -I*y, (6, 1) = -I*x, (6, 4) = -I*z, (6, 7) = -I*y, (7, 4) = -y, (7, 6) = I*y, (8, 3) = y, (8, 5) = I*y})

av, AV := LinearAlgebra[Eigenvectors](Hso)

Error, (in Polynomial:-Quadratic) type `truefalseFAIL` does not exist

This does not happen in Maple17.

## Not working simple example(differential equation)...

My code :

> restart; with*PDEtools;

> PDE := diff(u(x, t), `\$`(t, 2)) = 4*(diff(u(x, t), `\$`(x, 2)));

> pdsolve({PDE, u(x, 0) = cos((1/2)*x), (D[1](u))(x, 0) = 0}, u(x, t));

And i get Error, (in pdsolve/BC) invalid input: indets expects 1 or 2 arguments, but received 3.Please help me find my Error.Thank you!!!

## Error message: "Error, (in F) invalid input: F use...

The following procedure is intended to recursively generate all vectors in the set of n dimension vectors with elements 0 to p-1. If I use a fixed value for p it works fine, but as soon as I introduced p as an argument it gives the error "Error, (in F) invalid input: F uses a 2nd argument, n, which is missing".

```F:=proc(p,n)
if n=1 then:
return [seq(Vector([x]),x=0..(p-1))];
else:
return [ seq(seq(Vector([v[],xn]),v in F(n-1)),xn=0..(p-1)) ];
end if:
end proc:

F(3,2);```

I cannot for the life of me figure out what is wrong with the above code? Can anyone enlighten me?

## Error message: "Error, (in F) invalid input: F use...

The following procedure is intended to recursively generate all vectors in the set of n dimension vectors with elements 0 to p-1. If I use a fixed value for p it works fine, but as soon as I introduced p as an argument it gives the error "Error, (in F) invalid input: F uses a 2nd argument, n, which is missing".

```F:=proc(p,n)
if n=1 then:
return [seq(Vector([x]),x=0..(p-1))];
else:
return [ seq(seq(Vector([v[],xn]),v in F(n-1)),xn=0..(p-1)) ];
end if:
end proc:

F(3,2);```

I cannot for the life of me figure out what is wrong with the above code? Can anyone enlighten me?

## How to get a numerical answer using the erf functi...

I didn't even know the erf function existed until doing this problem. I looked up how to use it, so I tried plugging in the explicity form into Maple, hoping it'd solve it, but it just spit back out the erf function.

I am trying to get a number answer.  A decimal. Because this is calculating a probability. How do I get Maple to give me a number here? Thanks!

## How to catch Maple Error?...

Sometimes I got an error (purple in output). How can I catch on programming level?

I mean I want to do smth like: if <error> -> then <action>

## How to catch Maple Error?...

Sometimes I got an error (purple in output). How can I catch on programming level?

I mean I want to do smth like: if <error> -> then <action>

## Getting the error of "Error, (in simplify/table) t...

Maple Worksheet - Error

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

Hello, Maple is giving me the error:

"Error, (in simplify/table) too many levels of recursion"

Once I take the integral of an expression I am getting the error. It starts at the first integral of the document.

Note: If I make another maple worksheet and write the expression of the integral without writing it shorthand by substituting the functions in it seems to give me an answer.

For example instead of the integral of say, y(x)*f(x) I would write out the definitions of the functions in the integral and it would give me an answer while the former would give me the error.

I have uploaded the document, Any help would be appreciated. I'm not sure if there is a fix or not. Thanks

## Where is the error?...

Hello,

I tried to define the Poisson bracket in this way

restart:
Ps:=proc(f,g)
local P;
P:=simplify(diff(f,P[1])*diff(g,X)-diff(f,X)*diff(g,P[1])+
diff(f,P[2])*diff(g,Y)-diff(f,Y)*diff(g,P[2]));
end;

The problem is that, if I ask Ps(P[1],X) I got 0 which is clearly wrong.

Where is the error?

https://dl.dropboxusercontent.com/u/51122291/Scrreshot.jpeg

Thanks Nicola

## solve ODE equation by dsolve ...

I have tried to solve the following ode equation, but I have got error. What is the potencial problem?

http://i65.tinypic.com/xdcl8p.jpg

## Why is Determinant often incorrect for matrices wi...

When I use the Determinant function on a matrix with (single variable) polynomial entries with real coefficients I often get an incorrect answer. I know the answers are incorrect because they have a higher degree or a lower lowest degree than is possible given the matrix elements.

However, when I replace the coefficients in the polynomials with rational numbers or I put in the option method=minor, I get the correct answer.

The problem seems to be roundoff error. However, the important error is not simply small changes in the resulting polynomial. The important error is the presence of entirely incorrect powers of the variable and not with very small coefficients.

How does this happen and why does the help page for Determinant( ) not warn of this behavior? In particuiar, why does the help page not say that using Gaussian elimination (i.e., the default) will often give incorrect answers in such cases, but using method=minor will work? Is this behavior known? I cannot find any reference to it on the internet.

## Error, too many levels of recursion...

In Maple V, Release 4 (1996):

 T:=table():i:=1:N:=5000;for i from i to N  do   T[i]:=T[i+1]:   T[i+1]:=1;   eval(T[1]);od:print(i);for i from i to N  do   T[i]:=T[i+1]:   T[i+1]:=1;   eval(T[1]);od:print(i);

N := 5000
Error, too many levels of recursion
3607
5001

Can You explain this occurence, as well as the following one:

In Maple V, Release 4 (1996):

 T:=table():i:=1:N:=5000;for i from i to N  do  T[i]:=T[i+1]:  eval(T[1]);od:print(i); for i from i to N  do  T[i]:=T[i+1]:  eval(T[1]);od:print(i);;

gives:

N := 5000
Error, too many levels of recursion
3607
Error, too many levels of recursion
3607

How does one control allowance for recursion depth?

## why do i have a problem?...

Two weeks ago i didn`t have problem with calculate and plot this pareto`s frontier. I got plot it, but if i try it now, i can´t . Why?.

Before

f1 := (1+x1^2+4/3*(x2^2+1))/(x1+x2); f2 := (1+x1^2+3/4*(x2^2+1))/(x1+x2);

with(plots); with(Optimization); ind := 1; ans := Array(); for i from 1.73205080756887853 by 0.1e-4 while i < 2.87500000000000000 do roll := i; f1max := NLPSolve(f1, {f2 = i}, x1 = 0 .. 2, x2 = 0 .. 3, method = sqp, maximize = false); ans := proc (ind) options operator, arrow; [op([1], f1max), roll] end proc; ind := ind+1 end do; ans;

st := time[real]();

Array(%id = 18446746983952876598)

pointplot(convert(ans, list));

After

with(plots); with(Optimization); ind := 1; ans := Array(); for i from 1.73205080756887853 by 0.1e-4 while i < 2.87500000000000000 do roll := i; f1max := NLPSolve(f1, {f2 = i}, x1 = 0 .. 2, x2 = 0 .. 3, method = sqp, maximize = false); ans := proc (ind) options operator, arrow; [op([1], f1max), roll] end proc; ind := ind+1 end do; ans;

st := time[real]();

ans
pointplot(convert(ans, list));
Error, (in plots:-pointplot) number of elements in list must be a multiple of 2  (????)

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