## how to addition three parameter in one equation?...

i need to addition my equation like that,but this does not working. i try to use the >'add(add(add(x*y+y*z+z*x+a,x=x1),y=y1),z=z1);' but get the wrong answer, the 'a' addition 4-times. this is my original procedure: > x1:=[1,2,3,4,5,6,7,8,9]; x1 := [1, 2, 3, 4, 5, 6, 7, 8, 9] > y1:=[9,8,7,6,5,4,3,2,1]; y1 := [9, 8, 7, 6, 5, 4, 3, 2, 1] > z1=[4,5,6,3,2,1,9,8,7]; z1 = [4, 5, 6, 3, 2, 1, 9, 8, 7] > eq1:=add(x*y+y*z+z*x+a,{x=x1,y=y1,z=z1}); # 'a' is a const. Error, wrong number (or type) of parameters in function add

## How do I plot a square?...

I've been trying to figure this out for the life of me and I keep getting an error somewhere. I'm trying to set it up so I have values for all four sides so I've used an array of variables to assign the values.. ie: [0,1] [1,1] [1,0] [0,0] but when i try and combine all of these in the plot, I get an error. Any help would greatly be apperciated. Thanks!

## Changing minimums over a two-variable function....

I'm currently in first year calculus, so my knowledge is limited, please forgive me. I've been given an assignment, and a part of it has me rather stumped (the teacher likes to give out questions before she teaches you how to do them). We are given 3 single-variable functions (domain is 0 <= x <= 40): `h1 := x-> -5 * ( 1 - x^2 / 1600 ) * sin ( ( Pi * x ) / 1600 * ( x / 2 - 3 ) * ( x / 2 - 20 ) )^2;` `h2 := x-> -5 * ( 1 - x^2 / 1600 ) * sin ( ( Pi * x ) / 1600 * ( x / 2 - 6 ) * ( x / 2 - 20 ) )^2;` `h3 := x-> -5 * ( 1 - x^2 / 1600 ) * sin ( ( Pi * x ) / 1600 * ( x / 2 - 9 ) * ( x / 2 - 20 ) )^2;`

## Unknown errors...

Hi everybody, As a part of some general problem, I need to solve a system of non-linear ordinary differential equations.I try to get a numerical solution, so I use the "dsolve numeric" command. In same cases, the Maple print out two errors that I didn't find in his help instruction. The first one is: error, (in dsolve/numeric/bvp) cannot determine if this expression is true or false: 20*nerr

## what is wrong in my code...

Please see the message written by Douglas for the correct code.

## PointList constructor

Maple
From time to time people ask on this site or elsewhere whether modules in Maple can be used the same way as objects in object oriented languages. The answer is yes and no. Yes - because OOP behavior can be simulated with modules - certainly not with full blown functionality, but still. No - because that is usually not the best way to do things in Maple. Here is an example of creating a type and an 'object' exploring it, with few 'methods'.

## Central Difference Method - Second & Third Derivat...

g := x -> x^3+x^2-3*x; h := 0.01; x := 1; yaydone := (g(x+h)-g(x-h))/(2*(h)); OK, I did some poking through my book, and it shows how to solve for the first derivative using the Central Difference method, it actually took me quite a while to get this formula going. This will solve for the first derivative using the Central Difference Method. I didn’t understand the book at first and thought I was supposed to use The Derivative of g(1+h) minus The Derivative of g(1-h). This really had me boggled. So now I am able to solve for the first derivative using the Central Difference Method My question is how to solve for the second & third derivative. My book has no examples for solving for anything other than the first derivative. Thanks so much for the help guys, I truly do appreciate it and I truly hate the book that I got to learn from

## module...

hi it seems that i realy did not undersand modules in maple 10 so here I come with a few question... 1, is possible to use modules right as a objects like in c++? 2, i want to have an objects: point,list where i want make list of points "pointlist:=list, pointlist.new(2,5),etc.(few points)" and i want to get list of my points related to variable poinlist.... so i need: make a new type: "point" and object "list" which can handle data of point type... how canI do this?

## Maple 6 and the mouse wheel...

My mouse wheel doesn't work with Maple 6 and Windows XP. Many of my colleaques are complaining the same. How to fix this problem?

## Row echelon form of sparse matrices...

I have a 661x662 entry matrix with <= 3 non-zero entries per row. The entries are small integers, non-zero ones being stored in a list s. I initialize the matrix by

m:=Matrix(661,662,s,storage=sparse,datatype=integer[1]);

a:=ReducedRowEchelonFrom(m);

This operation takes half an hour. Is there any way to speed it up, eg. using the NAG routines?

Thanks,
Mak

## Lagrangian density...

Dear friends Is there any way (or any package,...) that can be used to find the density of the Lagrangian of a PDE. For example the nonlinear Schrodinger (NLS) equation has the form I*Diff(u,t)+1/2*Diff(u,x\$2)-abs(u)^2*u=0. This PDE may be considered as the Euler equation which follows from the Lagrangian with density L , L=I/2*(conjugate(u)*Diff(u,t)-u*diff(conjugate(u),t))-1/2*abs(u)^2-1/2*abs(u)^4. Now, could anybody please let me know about any way to find L from NLS? many thanks sayed

## Linear Programming...

Can anyone tell me how to input the following problem in maple?
Find the maximum value of C=3x+2y on the region determined by the constraints {3x+2y<=18, 0<=x and <=4, 0<=y<=5}

Any help will be greately appreciated. Thanks in advance<code>.

## how to solve this equation?...

this is the differential equation of second derivative. because i learn Maple not long. the equation name is 'eq5' > eq5:=D(D(x1))=(a1*fx1+a2*gx1)*D(x1)+(a1*fx2+a2*gx2)*D(x2)+(a1*fxt+a2*gxt); x1(t),in the file. if you interesting ,just download the file to help me to solve this problem. regards. View 1984_diff equ.mw on MapleNet or Download 1984_diff equ.mw
View file

## How to calculate symbolic formulas including matri...

I know the power of Maple for exact symbolic and numeric computing. With Maple, we can calculate symbolic formulas expressed with scalar values such as x, y, z, and so on. For example, ``` >> solve(x+z+1=0,x); x=-z-1 ``` However, I want to calculate formulas including matrices algebraically, too. I’ll show an example of my ideal result; ``` >> solve(A*x=b,x); x=A^-1*b or x=(A^T*A)^-1*A^T*b ``` In the example above, I assume A is a matrix, and x, b are vectors. “A^-1” means the inverse of the matrix A and “A^T” means the transpose of the matrix A. I want to keep “A” as a matrix and get a result like the equation which is often written in well-known textbooks of linear algebra.