## EASY question on error message...

Dear all! I don't use Maple very regularly and have come across the following error message: "Error, (in content/polynom) general case of floats not handled" This error message occurs when I try to differentiate a fairly simple function of one variable and various constants. The curious thing is the following (and that's probably crucial to the problem): when the constant d equals 1 (see attached file), Maple does the derivation without any problems. As soon as it is a decimal number (e.g. 0.9) the error message occurs (note: d is always smaller or equal to 1). Plus, when d is a decimal number all functions in my worksheet increase considerably in size. Maple doesn't seem to fully simplify them. I guess, this is the source of the problem.

## Integer Division...

Hi,

I had an issue where I wanted the quotient of two integers a and b; the quotient q from the division algorithm for a/b which finds a = b*q + r, 0 <= r < b

I was not sure how to obtain it. Since,

a := 7;
b := 3;
q := a / b; # returns fraction 7/3

Received some help from G. A. Edgar from Ohio State and Joe Riel from Maple; who clued me into the use of 'iquo' to obtain this.

a := 7;
b := 3;
q := iquo(a,b,'r'); # q = 2, r = 1

I was experimenting with floor(a/b), but I am sure this is more efficient (no conversion between fraction and integer);

There is 'irem' which just determines the remainder from integer division. The 3rd argument in iquo is optional ... and returns the remainder from the division.

## Showing steps...

How do I get Maple to show the old-fashioned, step-by-step solution of a a problem. I have tried to find this in "Help" but Maple's help is so disorganized as to be rather UNhelpful.

## How to use MmaTranslator?...

Good morning Maple experts, When I use FromMma() to the following expression: Test1 := ( T = {1, 2, 3}; Clear[v]; v[{}] = 0; v[{1}] = 1; v[{2}] = 2; v[{3}] = 3; v[{1, 2}] = 4; v[{1, 3}] = 5; v[{2, 3}] = 6; v[T] = 19;) I got only Test1:=T:=[1,2,3] The function I used was FromMma(`Test1:=( T={1,2,3}; v[{}]=0; v[{1}]=1; v[{2}]=2;v[{3}]=3;v[{1,2}]=4;v[{1,3}]=5; v[{2,3}]=6; v[T]=19;)`); 1. Where is my mistake? 2. What are the equivalent expressions in MAPLE? .. How may I write it without using MmaTranslator? Many thanks for the help!

## Question On Tensors...

I apologize if the forum is strictly for undergrad students. I'm now on the section of Arfken's text "Mathematical Methods..." that deals with tensors, and I'm having a little trouble. My problem is how to physically or intuitively, picture (for lack of a better word) tensors. This also adds to the problem of not fully understanding and appreciating the difference between covariance and contravariance, other than it seeming to be arbitrarily subscripting or superscripting the tensor elements. Thanks, dc

## Hotw to get the data from a 3d plot...

How do I get the data from a 3d plot in maple 9 to a .txt or .dat file so I can plot it in origin or whatever?

## Saving...

When I click the "Save" or "Save as" options in my maple work, nothing happens, I can't save what so ever, does anyone else have this problem and if so, how do I fix it?

## Maple 11 Introductory Programming Guide...

On page 121 of the 2007 edition of the Maple 11 Introductory Programming Guide in section 3.6 Exercises, problem 3, it says: "... Find the inverse of (a*b)/c+((a-d)/(b*e))*I) in standard form, where a, b, c, d and e are real." Here is my failed attempt: View 4937_Problem_3.mw on MapleNet or Download 4937_Problem_3.mw
View file details TIA

## IntTutor doesn't show me the trick...

Hi, let's say i want the Integration Tutor show me how to integrate a function. Sometimes i don't know what the next step is, so i click the get-hint button. When it says "can you do a change of variables?" then i sometimes can't because i still have no idea. So i click "next step" and the result is shown. But i want to know what the substitution actually was, because it't not always obvious. But Maple doesn't tell me, for example, "t=2x has been applied" or similar. What to do ?

## How to format numbers and save memory?...

Hello Maple friends, I have a loop like this: A := array(1..10); for i from 1 to 10 do A[i]:= [ i, i^2, evalf(i^(1/3))]; end do; print(A); Nevertheless I dont know the following things: 1. How may I format in the way that in the third column of my array I see only 3 decimals? 2. As my matrix "A" is very big.. it is this the best way to avoid memory problems or there is some way to reduce this problem? Thanks in advance for any help! Jean

## local optimization with Optimization package vs. f...

Hello Maple community!

As a part of a more complex (global) optimization problem I have a simple trigonometric parametrization of a classical probability distribution, i.e. just a list of positive number that sum up to 1. For test purposes, I take now one arbitrary element, p, of that probability list and use it as a target function for an optimization. Of course, one expects that one will find suitable parameter sets for minimizing/maximizing p. So here is my simple target function for the case of N=10 probabilities (requiring N-1=9 parameters):

objective := proc(x1, x2, x3, x4, x5, x6, x7, x8, x9)

## Motion of airplane...

I have found a very interesting physics problem which describes the motion of an airplane, it is a very simple math model. We use only two coordinates, x(t) and y(t), t is the time. The airplane starts at the point (0,a), a>0 and airport located at the origin (0,0). It leads to the differential system ( v0, w>0 are given ):
```sys_ode:=diff(x(t),t)=-v[0]*x(t)/sqrt(x(t)^2+y(t)^2), diff(y(t),t)=-v[0]*y(t)/sqrt(x(t)^2+y(t)^2)+w;

d                v[0] x(t)         d                v[0] y(t)
--- x(t) = - --------------------, --- y(t) = - -------------------- + w
dt                         (1/2)   dt                         (1/2)
```