hello , to solve a differential euqations , maple gave me this error. please help me.

TG.mw

Hi all,

I'm trying to initialize a 4-vector and promote it as a tensor in Maple 16 using the Physics package. My attempt so far has been unsuccessful :) 

This 4-vector needs to be a function of the coordinates X. What I'm trying to do is to allocate terms by terms my tensor as indicated in my attempt below. Everything looks fine (the query is telling me F2 is a tensor) but when I'm trying to compute contravariant quantities, I can't obtain an answer for a given coordinate (here F2[~n](X) is not equal du v_1(X))... Finally, the last line, computing the sum over all the indexes is not giving me an answer... 

restart; with(Physics):
Setup(mathematicalnotation=true):
Setup(coordinatesystems = cartesian):
Define();
g_[]:

F2[1]:=(x,y,z,t)->v_1(X);F2[2]:=(x,y,z,t)->v_2(X);F2[3]:=(x,y,z,t)->v_3(X);F2[4]:=(x,y,z,t)->1;

Define(F2[mu](X));

Define(F2,query);

F2[1](X);F2[2](X);

F2[~1](X);F2[~2](X);

F2[~nu].F2[nu]

Surely, something is wrong in my way of defining a spacetime tensor. What would be the solution to obtain a decent contravariant F2?

Another more or less related question would be to know how to compute a taylor expansion of a function itself i.e. 1/(1+f(X))~ 1-f(X) since f<<1? Would there be a built-in fonction to do such a thing?

Many thanks!

Vincent

Hello people in mapleprimes,

I hope you will give an answer to my following question.

This is a question of nonunit(algebraic) in patmatch.

In help page of maple this examples are on.

Case i)

>patmatch(a, A::(nonunit(algebraic))+B::(nonunit(algebraic)), 'la');

false

Case ii)

>patmatch(a,A::(nonunit(algebraic))+B::algebraic,'la'); la

ture

[A=a,B=0]

Is unit in the case of sum zero, so that in Case i) false is shown, though in Case ii) B=0 is returned?

Best wishes.

taro

Dear people in mapleprimes,

>define(INT, linear, conditional(INT(a::algebraic, X::name) = a*X, _type(a, freeof(X))), INT(X::name, X::name) = (1/2)*X^2);

>INT(2*x+4, x);

x^2 + 4*x

>INT(z+x, z);

(1/2)* z ^2+ x*z

is written in the help page of maple.

This code is to make a function INT.

What it means is that if INT(a::algebraic, x::name) then this is transformed into a*X, where a is independent from x.

And, INT(X::name,X::name) is transformed into (1/2)*X^2.

The first of what I want to ask you is the way of use of "_type", which is not in the help page, and as for names with "_" ahead, 

it is written that "_" means internal command for Maple, so not to use it. Is it right to use a name with "_" ahead of it here?

The second of what I want to know is the way to use "conditional."

Please teach me the meaning of this.

Thanks in advance.

I hope you will teach me the above questions.

Best wishes.

taro

seq(i,i=1..5);  gives output 1,2,3,4,5

seq(i,i=5..1);  seems to get ignored in Maple 7.  It does not return an error message.

I was hoping to step back from a large number to a smaller one in stepsof minus one.  The for loop structure allows negative "increments" - so I experimented by putting the decrement value of -1 between the two dots.  I was expecting it to givean error message, so was surprisd when it gavesome output!

eg  seq(i, i=5.-1.2);  gives output of 38, -1

I'm curious as to what is happening here?  Also, has the seq command been upgraded in later versions of Maple?  eg is it possible to do negative decrements?

Hi there,

I would like to know whether there is some way to print non-integer axis numbers for a given plot.

Let's say I have an array for an independent variable such as [0.5 1 1.5 2]. I would like Maple to use these values in the corresponding axis instead of printing the array indices [1, 2, 3, 4].

I would like to know how this is done for a surface plot.

Attached is the worksheet where "b" is such a parameter/independent variable: MapleSimulation_test11.mw

Thank you,

jon

I am just starting with Maple 18 on Windows 8.1. I did not like the default color palette for 2D graphs and tried another one. So I edited my maple.ini file, which was in 

Hi,

  Excuse me, I tried to substract in a series expansion. It works for Taylor-type expansion, but not Laurent-type ones

*********

ffff:=1/(t-3);
ggg:=taylor(ffff,t=infinity,3);
coeff(ggg,t,-1);

ffff:=exp(t);
ggg:=taylor(ffff,t=0,3);
coeff(ggg,t,1);

*********

Maple gives me

Error, unable to compute coeff

1

. My question is, why "coeff" does not work in the first case? how to make it work? Though I can copy the expansion part, assign it to another variable, and "coeff" will work

Excuse me,

  I have the following input

***

fff:=x1^k;
int(fff,x1=0..x2);

***

I would like to obtain

1/(k+1)* (x2^(k+1)), k<>-1

but maple gives me just the same integral. Is there any way to get the expression?

Thank you!

Hello,

Im solving 4 ODE equations with BC. im trying to shoot the initial value but im having this error:

""Error, (in isolate) cannot isolate for a function when it appears with different arguments""

anyone could help me???

shooting92.mw

Download shooting92.mw

I am trying to make a plot3d on my Surface Pro  3 running Windows8.1.

The plot looks like a ghost.  Pale grey.  It looked nice and colourful when I executed the same command on an older computer a few hours ago.  (I know it was exactly the same command because I saved the file on my old computer and then opened in on the Surface Pro 3)

Is there a way to fix this?

plot3d(-x^2+y^2-3*x+2*y+100, x = -5 .. 8, y = -5 .. 5, transparency = 0, lightmodel = light1, glossiness = 1, filled = true, style = wireframeopaque, shading = zhue, view = [-5 .. 10, -5 .. 8, 0 .. 150]);

 OOPS!  Now the problem has corrected itself.  

I'm getting worried about all the weird things Maple is doing on this Surface Pro 3.  I'm trying to make up a final exam tonight (the exam is tomorrow).

I have downloaded MaplePlayer on my iPad.   I see that it comes with a number of "pre-recorded" programs that it can run.  Is there a way to have it run a Maple worksheet that I have written?   If so, how do I use this app to open an existing worksheet? 

Also, are there any plans for this app on the Android platform any time soon?

I have written a program and at one point I have an assignment statement like BG(i, j) :=1    When ever I run the program, I get a dialog box which asks me to choose between "function definition" and "remember table assignment."  Is there a way to tell the program that I want this to be a table assignment in the code so that I don't always have to answer the question?

I have written a program and I would like to embed a check near the beginning to see if input data was entered correctly.  I have written an "if statement" to check on this and I would like the program to stop execution at this point if the "if statement" criteria are met.   I get an error saying that this command is disabled.   I have tried "stop", "end" and "quit," as I understand that they are all the same.

Where u and v are the displacement components in x and y directions respectively.