## Find an integer...

Dears,

Consider the problem min{|a+2*i| : i integer}, where a is a number of the form 2k*t for a fixed integer k>1 and t in [0,1]. A simple checking shows that i must belongs to the interval [-(1+a)/2,(1-a)/2] and as the legth of this interval is 1, there is two integers in this interval.

How can I compute this integer i with Maple? The commad "ceil" not seem very suitable. Some idea?

## using @ for multiple applies...

Say I want to use multiples commands on an expression

simplify(expand(eval(expr,x=y+1)))

Now similar I could use

(simplify@expand)(expr)

but how do I do it with sth like eval which needs extra arguments

(simplify@expand@eval(x->y, x=y+1))(f)

??

## plot functions in the same figure...

i want to plot these four functions in the same graphe f(x)=1/1+x^2 on the intervalle [0,1] also the second function the line curve that connects the two points(0,f(0)) and (1/3,f(1/3)), the third function the line curve that connects the two points (1/3,f(1/3)) and (2/3,f(2/3)), the fourth function the line curve that connects the two points (2/3,f(2/3)) and (1,f(1))

can anyone help me ?

## combine while excluding a variable...

I have this expression:

-sin(alpha)*(sin(theta1)*cos(theta)-cos(theta1)*sin(theta))

which can be combined using a trigonmetric formula...

However when using combine() it also tried to sneak alpha into the result...

Is it possible to freeze the variable alpha when combining?

## Definition of Matrix after restart changed to _rta...

I'm having sone trouble with my matricies after running restart. When creating the matrice, everything is fine and they are defined as normal. But, if I run restart and try to erdefine them, they are defined as some form of

The only way I've been able to fix this besides restarting Maple is to either add or remove the colon after the matrix, depending on wether there was one. If ther was, when I remove it the matrix is defined normally and vice versa. I'm relatively new to Maple coming from Matlab and would like to start using it more, but this matrix thing is very frustrating. I've attached a copy of the maple file. Thanks

First definition, everything is normal:

## Contraction in Physics package...

So I have the following:

restart;
with(Physics):
Setup(mathematicalnotation=true,coordinatesystems=cartesian);
Define(A[mu](X));

First of all X ist defined in terms of (x,y,z,t). Is is also possible to define it in terms of (t,x,y,z) with t being mu=0.

When I do

alias(X=(t,x,y,z))

this applies only to this one vector and

d_[4] is still the time differentiation, right?

Then I wanted to construct the divergence

d_[~mu] A[mu](X);
TensorArray(%,performsumoverrepeatedindices=true);

This should give me sth like d1 A1 + ... + d4 A4, but it stays with d_mu A_mu ?!?

Why?

Is there also a "function" which does the contraction?

So if I have

f[mu,nu]=d_[mu] A[nu](X)

eval(f[mu,nu],nu=mu)

contract(%)

??

## How do i open this maple document?...

Hey MaplePrimes

I have a problem with opening some of my documents in maple. When i try to open them, a box pops up with the text "How do you want to open this file?" with the options "Maple Text, Plain Text, Maple Inputs". None of these options work (document is blank) and "Plain Text" and "Maple Inputs" causes maple to crash. Is it possible to recover the documents?

ps. when i try to upload one the documents this happens:

Maple Worksheet - Error
Failed to load the worksheet /maplenet/convert/Maple_docs_til_mat.mw .

## interface() problem...

I want to suppress  ~ when using assume()

I write:

restart;
interface(showassumed = 0);
assume(s>0);
s;

but s still appears with tilde?!?

## applyrule for different expressions...

restart;

eq1 := a[n+2]+4*a[n+1]+10*a[n]-5*n-1;

applyrule(a[n::anything] = n*p+q+b[n], eq1);

eq2 := a(n+2)+4*a(n+1)+10*a(n)-5*n-1;

applyrule(a(n::anything) = b(n)+n*p+q, eq2);

eq3 := a(n+2)+4*a(n+1)+10*a(n) = 5*n+1;

applyrule(a(n::anything) = b(n)+n*p+q, eq3)

So my question is: Why does the first one not work? the second one works as expected, but the third one again does not?!

## Trouble entering a partial differential equation i...

Good morning,

I've been having some trouble entering this expression in Maple 17.

My teacher suggested using this format, however, this format is from 2004 and certainly isn't recognized by the current version of Maple, as it keeps spitting back 0=0 no matter how many different ways I try to enter it.

Could anyone provide feedback on the correct syntax of how to enter this expression? Thank you very much for your time.

## ode bvp fluid problem...

how may i encounter this problem,

 >
 >
 >
 >
 (1)
 >
 (2)
 >
 >
 >
 >
 (3)
 >
 >
 >

h bcs

Is is possible to tell the latex output what to do if it finds a symbol?

Suppose I have the following expression:

O3^2 + k_O3NO

The normal latex output just takes it as it is and also translates k_O3NO to k_O3NO with the underscore.

I however want it to read (latex notation in math mode)

\left[ \text{O}_3 \right]^2 + k_{\text{O}_3\text{NO}}

So is that possible without changing everything manually?

edit: Just as a remark, the output at the moment for this expression reads

{{\it O3}}^{2}+{\it k\_O3NO}

and is kinda awful if compiled in latex...

Is it also possible for maple to latex realizing where a line-break is necessary?

## Plot of coupled functions and extraction of the da...

Hello.

I'd like to plot two coupled functions x=x(t) and y=y(t) given by expression R0 and R1 (see below) for the interval t=0.001..0.999 and then after that extract tha data from the graphs for functions x(t) and y(t).

How can I do that in easiest way?

I will appreciate you.

## Maple17 performance on a simple integral of ration...

Dear all,

I've just discover something quite surprising for me... It turns out like if Maple didn't take in account the linearity of the integral.

In the middle of a calculation, I need to compute the following integral

int(3628800 / (y * (1 / 2 + y)^11) - 3628800 / (y * (39 / 2 + y)^11), y = 39 / 2..infinity);

Maple 17 is not able to instantly answer me, and I'm not so patient... (I've waited more than 30s)

Nevertheless, if I ask Maple 17 to compute

3628800 * int(1 / (y * (1 / 2 + y)^11) - 1 / (y * (39 / 2 + y)^11), y = 39 / 2..infinity);

as well as

int(3628800/(y*(1/2+y)^11), y = 39/2..infinity)-int(3628800/(y*(39/2+y)^11), y = 39/2..infinity);

Maple 17 answer me instantly... which turn out to be quite surprising!

Is there someone, here, who has some ideas of what is happening in this calculation? Why Maple17 has this strange behaviour?

Tolliob

## Simplification of Expression...

Why does

5103*&Omega;*(5*sqrt(7)+16)/((1+2*sqrt(7))^(3/2)*(7+2*sqrt(7))*(-2+sqrt(7))*(14+sqrt(7))*(2*sqrt(7)-1)*(4+sqrt(7)))

not simplify to

sqrt(1+2*sqrt(7))*&Omega;

???

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