## skipping time consuming calculations in a loop...

I am looping over a list of functions to calculate various properties of the said functions. some of these calculations take too long. I was wondering if there was a way to skip to the next element of the loop if a calculation takes more than a specific time.

## I looking to buy maple latest edition...

I looking to contact a maple sales representative. I am from india I am not getting any contact number. Can anyone help.

Kind help anyone if possible. I do research in mathematics  field but at a personal level. I need help on which product to buy and a sales represitive number or someone to contact me so that i can first understand certain doubts from my personal end then I can opt for.

## Solving PDE for a function of a function....

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I need to solve a system of coupled partial differential equations. I would like to search for a function of 4 variables but such that two of the variables only appear in a particular combination.

F(theta,r, phi*(a^2+r^2)-at).

Is there a way to enforce this?

## How loops with multiple lines?...

I'm trying to put a relatively elaborate peace of code in a loop, but can't figure out how to have multiple lines. Each command separated by ';' is awkward and seems to cause me to make even more typos then normal and it's hard to read the code.

Is there a way to have command on separate lines with in a loop?

-Arthur

## ifactor of large integers...

I used Maple to factor (using ifactor) the number 10^128 + 1.  Maple produced the factors in a matter of seconds.

One of the factors had 116 digits.  I then restarted Maple and executed the command ifactor(X) where X was the

factor with 116 digits.  Maple found the number was prime instantly.  I do not understand how one can determine

that a number  with 116 digits is prime in less than a second.  My guess is that Maple has stored some large primes.

Also I used  Maple to factor (10^128+3) and I turned the program off because it was taking forever.

## How to plot this Equation in Runge-Kutta 4th-5th O...

I am trying to solve this equation in RK Method 4th-5th Order but the following error keeps happening.Please help me to solve this equations.
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## How do handle float undefined in my data...

The matrix data[gridji,4] in my code has float undefined. Please, how do I handle it?

## Where is the problem in my loop which increases th...

In part of my program, I have a loop that the iterative calculations are performed there. During running the program when it comes to the loop the memory usage become full in a short period of time and I face the memory shortage. Since my program is so long and huge, I only can show the loop part of it here, you may look at where is the problem of high memory usage in loop and how to deal with it. Any comment will be appreciated.

I again note that, this segment can not be run independently since it is a part of big program. I put it just to see and mmake comment if any.

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External force

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Loop

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## how to use "proc"...

Hello everyone,

I want to use "proc" in a program. Although the original code is good for me, I modify it by "proc" to be convenient. Thank you very much!

With regards


clearall;
restart;
Digits := 15;
## Initial polygon
x[1] := [-1, 1/2, 1, 0, -sqrt(2)/2, -1, 1/2, 1, 0, -sqrt(2)/2, -1, 1/2, 1, 0, -sqrt(2)/2];
y[1] := [0, sqrt(3)/2, 0, -1, -sqrt(2)/2, 0, sqrt(3)/2, 0, -1, -sqrt(2)/2, 0, sqrt(3)/2, 0, -1, -sqrt(2)/2];
s2 := [-1, 1/2, 1, 0, -sqrt(2)/2, -1];
t2 := [0, sqrt(3)/2, 0, -1, -sqrt(2)/2, 0];
assign(a[-6] = 13/1296, a[-5] = -11/648, a[-4] = -1/16, a[-3] = -107/1296, a[-2] = 179/1296, a[-1] = 9/16, a[0] = 137/144, a[1] = 137/144, a[2] = 9/16, a[3] = 179/1296, a[4] = -107/1296, a[5] = -1/16, a[6] = -11/648, a[7] = 13/1296);

L := 3;
N := numelems(x[1]);
## Perform k-1 iterative steps
# L--the number of iterations; nk--the number of refined points after k steps;
for k to L do
nk := 3^(k - 1)*(N - 6) + 6;
for i from 3 to nk - 2 do
x[k + 1][3*i - 8] := a[-6]*x[k][i + 2] + a[-3]*x[k][i + 1] + a[0]*x[k][i] + a[3]*x[k][i - 1] + a[6]*x[k][i - 2];
y[k + 1][3*i - 8] := a[-6]*y[k][i + 2] + a[-3]*y[k][i + 1] + a[0]*y[k][i] + a[3]*y[k][i - 1] + a[6]*y[k][i - 2];
x[k + 1][3*i - 7] := a[-5]*x[k][i + 2] + a[-2]*x[k][i + 1] + a[1]*x[k][i] + a[4]*x[k][i - 1] + a[7]*x[k][i - 2];
y[k + 1][3*i - 7] := a[-5]*y[k][i + 2] + a[-2]*y[k][i + 1] + a[1]*y[k][i] + a[4]*y[k][i - 1] + a[7]*y[k][i - 2];
x[k + 1][3*i - 6] := a[-4]*x[k][i + 2] + a[-1]*x[k][i + 1] + a[2]*x[k][i] + a[5]*x[k][i - 1];
y[k + 1][3*i - 6] := a[-4]*y[k][i + 2] + a[-1]*y[k][i + 1] + a[2]*y[k][i] + a[5]*y[k][i - 1];
end do;
end do;
## Plot the result
s1 := evalf(simplify(convert(x[L+1], list))):t1 := evalf(simplify(convert(y[L+1], list))):
f1 := <<s1> | <t1>>: f2 := <<s2> | <t2>>:
plot([f1, f2], linestyle = [1, 3], color = [black, red]);

T5Scheme:=proc(x[1],y[1],L)
local i,k,nk,result,N,a[-1],a[7],a[6],a[5],a[4],a[3],a[2],a[1],a[0],a[-2],a[-3],a[-4],a[-5];          N:=numelems(x[1]):
for k from 1 to L do
nk := 3^(k - 1)*(N - 6) + 6;
for i from 3 to nk - 2 do
x[k + 1][3*i - 8] := a[-6]*x[k][i + 2] + a[-3]*x[k][i + 1] + a[0]*x[k][i] + a[3]*x[k][i - 1] + a[6]*x[k][i - 2];                       y[k + 1][3*i - 8] := a[-6]*y[k][i + 2] + a[-3]*y[k][i + 1] + a[0]*y[k][i] + a[3]*y[k][i - 1] + a[6]*y[k][i - 2];                  x[k + 1][3*i - 7] := a[-5]*x[k][i + 2] + a[-2]*x[k][i + 1] + a[1]*x[k][i] + a[4]*x[k][i - 1] + a[7]*x[k][i - 2];                  y[k + 1][3*i - 7] := a[-5]*y[k][i + 2] + a[-2]*y[k][i + 1] + a[1]*y[k][i] + a[4]*y[k][i - 1] + a[7]*y[k][i - 2];                   x[k + 1][3*i - 6] := a[-4]*x[k][i + 2] + a[-1]*x[k][i + 1] + a[2]*x[k][i] + a[5]*x[k][i - 1];
y[k + 1][3*i - 6] := a[-4]*y[k][i + 2] + a[-1]*y[k][i + 1] + a[2]*y[k][i] + a[5]*y[k][i - 1];                   result[1]:=x[L+1]:           result[2]:=y[L+1]
end do;
end do;
return result
end proc:


## Can I insert a Hyperlink to a Geogebra document?...

I would like to insert a hyperling to a geogebra document but the hyperlink box deosn't appear to allow general files. Can this be done?

## It may seem like a stupid question. ...

It may seem like a stupid question, but why is the first answer not complete, but the second imput is the same as what the book states?

I know you dont need to be able to read Dutch to understand that A = amplitude (amplitude), Omega = Hoekfrequentie (Angular frequency), and Varphi= Fasehoek (phase angle).

They state that fc(0)= A*e^i*varpi, but it clearly shows that the equation on the left of the equal sign gives a "2" and on the right it gives "2+ 2*i*sqrt3".

Why is this so? It does not make things more easy if you can make "mistakes" like that by just asking the answer, but maple spits out half an answer...

He thanks a lot guys!

Greetings,

The Function

p.s.
I scanned my math books, i like it, i can search in the book now with the "ctrl+f" function in Adobe reader. Get a scanner. Mine is a Canon Lide 400. Not regretting it.. :)

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## What does this error mean in pdsolve?...

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I am trying to solve these two coupled PDE and am getting this error. Does anyone know what this mean?

## how to reduce evaluating time...

What should I do to reduce evaluating time?

 > restart;
 > with(plots):
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 > F:=kappa->kappa;
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 > f:=(alpha,delta)->exp(-abs(F(kappa))^2*(1+delta^2)/2-abs(F(kappa))*alpha)/abs(F(kappa));
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 > L:=(alpha,delta,Lambda)->(lambda^2*exp(-alpha^2/2)/4)*(Int(f(alpha,delta),kappa= -infinity..-Lambda)+Int(f(alpha,delta),kappa= Lambda..infinity));
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 > evalf(L(4,1,0.001));
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 > g:=(beta,delta)->exp(-I*kappa*beta-abs(F(kappa))^2*(1+delta^2)/2)/abs(F(kappa));
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 > E:=(omega,gamma)->exp(I*omega*gamma)*(1-erf((gamma+I*omega)/sqrt(2)));
 (6)
 > J:=(alpha,delta,Lambda,beta,gamma)->(lambda^2*exp(-alpha^2/2)/8)*abs(Int(g(beta,delta)*(E(abs(F(kappa)),gamma)+E(abs(F(kappa)),-gamma)),kappa=-infinity..-Lambda)+Int(g(beta,delta)*(E(abs(F(kappa)),gamma)+E(abs(F(kappa)),-gamma)),kappa=Lambda..infinity));
 (7)
 > #evalf(J(4,1,0.001,8,3));
 > N := (beta,alpha)-> (J(alpha,1,0.001,beta,3)-L(alpha,1,0.001))/\lambda^2;
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## is there a problem with MaplePrime?...

Is there a problem with Maple primes?

When I want to ask a question, the input panel is disabled and not possible to type into it. Here is screen shot.

Same when I wanted to make a reply to an answer. I can not type into the window that shows. It is like disabled.

I found I only can write here, in the post section.

What is the problem?