## LinearSolve gives wrong answer?...

Hello, all! I have a linear system of real numbers. I copied the example in the tutorial for using LinearSolve and converted my matrix to a float: with(LinearAlgebra); my_solve := proc(A::Matrix) local sz, local_A, B, sol; sz := Dimension(A); local_A := Matrix(A, datatype=float); B := Vector(1...sz[1], 1); sol := LinearSolve(local_A, B); end proc; And when it solved, it got the wrong answer!! It would produce a solution that simply didn't work. When I removed the float conversion step, and just used my original matrix, it worked perfectly. I would love to understand this better... is it because of rounding?

## Working with an array...

I am having issues creating an array and dividing by the values in the array. Any tips on how to make this a quick and painless process?

## How do you set up document headers?

by: Maple
I use Maple 10 in Document Mode. How do I set up page headers and footers in a document so when it prints one can see the document title, date,, page number, etc.?

## Curve Fitting Graph...

I know how to use the Curve Fitting Assistant to generate the least squares regression line for my data points. However, I need the graph of those data points and the regression line shown in the Assistant itself (with the circles / red line). How do I past / recreate that graph in the document itself?

## Splitting terms based upon variable dependency

by: Maple
I've had considerable difficulty in integrating products of trig functions with Maple. It usually expands the trig functions into forms that just are a mess to deal with. So, I usually handle this by splitting an expression into two parts: a constant term that doesn't depend upon the integration variable and a dependent term. In the past, I've usually done this by hand but have now created a procedure to do this automatically.

## Help Understanding the Working of a Procedure...

Here's an example procedure that I need help with in order to figure out how it produces certain cases of it's output. First, in the case when the argument n is negative does the procedure call itself again in the denominator of the fraction and return the value of the last line of the procedure (inside the inner call to itself)? I also assumed that the special identifier procname was not in unevaluation quotes in order to allow evaluation. Next, I also don't understand how the output for cases when the exponent n is even is produced. What's really confusing is the use of the anonymous mapping (x -> x.x), and also the meaning of the entire expression after the word then. Is that a multiplication of the two expressions in parentheses ? i.e. (x -> x.x)(procname(X, n/2) > Pow := proc(X, n::integer) if n <> x.x)(procname(X, n/2)) else X.procname(X, n-1) end if end:

## what's wrong? int(f,x)...

Hi! i want to know the length of sin(x) from a to b. This function sqrt(1+cos(x)^2) >= 1 int(f,x) must be > 1 So...try to do it,plot, and see what happen. is correct?

## Toda Lattice Second Order Coupled Differential Equ...

Hello, I am trying to analyze the numeric solution to the following equations - now what I want to do is a little different, I want to plot u_(n)(some number) as a function of n. This would show me the progression through the particles/distance rather than with respect to time. Here is the code: > with(DEtools): > n:=5: #(n can be as large as 500..) > > sys:=[seq(diff(u||i(t),t\$2)=exp(u||(i+1)(t)-u||i(t))-exp(u||(i)(t)-u||(i-1)(t)),i=2..n-1)]: > eqn1:=diff(u||1(t),t\$2)=exp(u||(2)(t)-u||1(t))-exp(u||(1)(t)-u||(n)(t)): > eqnn:=diff(u||n(t),t\$2)=exp(u||(1)(t)-u||n(t))-exp(u||(n)(t)-u||(n-1)(t)):

## Duplicates on lists....

Hi Hope anyone can help. When using this syntax in Maple 10: >restart:_EnvAllSolutions:=true: f:=(x,y)->x^3*y-2*x^2*y+x*y^3; GRAD:=[diff(f(x,y),x),diff(f(x,y),y)]; STATS:=solve(GRAD,[x,y]); I get the following output: 3 2 3 f := (x, y) -> x y - 2 x y + x y 2 3 3 2 2 GRAD := [3 x y - 4 x y + y , x - 2 x + 3 x y ] STATS := [[x = 2, y = 0], [x = 0, y = 0], [x = 0, y = 0], 2 [x = 5/4, y = 1/4 RootOf(_Z - 5, label = _L2)]]

## Tablet PC Operation

by: Maple
Hello, I have tried to run the Maple 10 program on my Toshiba Tecra M4 TabletPC and it runs fine until I go to Tablet Mode. The only part of the program that will run in Tablet mode is the Classic Worksheet. The symptoms are that the windows that appear in say the documentation mode (in Tablet Mode) come up but are solid gray. The program seems to hang. Now what I mean by "Tablet Mode" is that you flip the touchscreen around and lock it on top of the keyboard. This cause the display to go from a horizontal presentation to a vertical sheet of paper presentation. Regards, Dave

## How do I make 3D surface plot from Matrix?...

Hi, How to make surface plot from elements stored in matrix of form [x,y,z]? Let's suppose I have the following matrix: >A:=matrix([[1.00, 1.00, 167.76], [1.00, 2.00, 95.588], [2.00, 1.00, 500.64], [2.00, 2.00, 335.51]]); The first argument from the lists is value for X axis, the second argument is value for Y axis and the third argument is value for Z axis. For example: x=1, y=1, z=167.76 x=1, y=2, z=95.588 x=2, y=1, z=500.64 x=2, y=2, z=335.51 How to make such plot in 3D?

## Maple's 3 Valued Logical System...

Is Maple 10's logical system called a three valued one simply because of the value FAIL, in addition to the truth values true and false ?