## New info on the label=...

New info on the "label=" question. I open a new work sheet and enter solve({x^2-y^2=y,2*x*y*=x}). The answer returned includes RootOf(_Z^2-3, label=_L2). Then I copy and paste that solve command after the next prompt and solve the same exact problem again. This time I get the same exact answers EXCEPT that the label is now _L5 and if I solve the same exact problem a third time I get a third label. I can only conclude that the label has nothing to do with the solutions to the problem. This makes me wonder what then is the purpose of a label? Why is it returned? What significance should one attach to it? I don't want to get bogged down about what the spec says or whether this is a bug.

## Datasets in Maple...

I would like to import a big dataset in Maple and this is giving me some difficulties. Although Maple does have an Importdata-command, I can't figure out exactly how it works. The dataset I want to import is an excel file consisting of 2000 observations with 7 variables. Can this be done and made usefull in Maple, or do I really have to sit down and learn SAS..?

## Maple 11 Introductory Programming Guide Exercise 1...

View file details I'm going through the introductory programming guide for maple 11, and I recently worked on some exercises. Instead of just computing, I tried to create a procedure for the first exercise of exercise set 1.6 on page 21.

## genmatrix when unkowns are functions...

I have a system of equations where unkowns are functions of variables ` > eqns:= {a(s,y,z,t)+2*b(s,y,z,t)=0,3*a(s,y,z,t)-5*b(s,y,z,t)=0}; ` I would like to get the matrix associated to the system. I tested genmatrix but maple returns `equations are not linear ` Anyone have an idea of how to do this?

## Label=_L2...

I get RootOf(_Z^2-3, label = _L2) in an answer. My understanding is that RootOf _Z^2-3 would be a root of Z^2-3=0 or plus or minus the square root of 3, but after reading the RootOf help sheet I still cannot figure out what label = _L2 means. My gut feeling is that it means one of the two roots, either -sqrt(3) or +sqrt(3) but that bothers me because I think that both are ligitimate solutions to the problem. Could someone please explain what label = _L2 means? The help sheet says something about label=e where e can be anything which wasn't at all helpful. Thanks. P.S. The problem that provided this issue is solve({x^2-y^2=y,2*x*y=x}) and in the second equation the x on each side should not be cancelled because x=0 is one solution.

## Animation and Maplet...

I would to get some ideas on how to write a maplet code that will animate step by step how to draw a rectangle ABCD: Draw side AB, and after this is done without removing side AB, draw side BC, and after this done without removing sides AB and BC, draw CD, and after this done without removing AB, BC and CD, draw DA. Although this is not really my problem, it is similar to the animation I am trying to create. Rectangle ABCD is constructed without user intervention. Thank you for any assistance you may come up with.

## Do I have this right then?...

Using _EnvAllSolutions:=true; with solve(sin(x)=1,x)the answer returned is 1/2Pi+2Pi_Z1~. The Maple User Manual on page 82 says that Maple uses variables of the form _ZN~ to represent arbitrary integers thus my understanding is that the answer returned can be interpreted as 1/2Pi+2nPi where n is any integer. Correct? Now for the more difficult situation where I an not sure my understanding is correct. Using _EnvAllSolutions:=true; with solve(sin^2(x)/x,x)the answer returned is Pi(2_Z1~+_B1~). In this case, the -Z1~ is again any arbitrary integer but _B1~ is quite different. Using about(_B1~) the return tells me that _B1~ is assumed to be : OrProp(0,1).

## Ok, I read ?solve but.......

I am having this common problem when solving trig equations. I read "?solve" but missed something somewhere because I still don't know how to solve this problem. Taking a simple example of solve(sin(x)=1,x) the answer returned is Pi/2 and while Pi/2 is a correct answer, because of the periodic nature of the sin function there are others. So maple for some reason (which doesn't make sense to me at all)is limiting the range/domain and therefore not providing the complete answer which is Pi/2 +2nPi where n is any integer. I tried to force Maple to consider a larger range by using assume(0<>

## Arrow key in Maple classic under Linux...

I installed Maple 11 into my Ubuntu 7.04 machine, and I'm having a problem to make the arrow keys work when I running maple classic worksheet. All the other keys on my keyboard works fine, but Maple won't response when I hit the arrow keys(up, down, left, right). It's a problem that only shows up in "Maple classic" (xmaple -classic). Any suggestions?

## Is this a bug?...

When I enter solve((sin(x))^2/x=0,x) in Maple 11, nothing is returned. When I enter the same thing in my voyage200 calculator, the correct answer of x=@n1*Pi where @n1 is any integer constant is returned. Why can't I get maple to produce the correct answer? Is this a bug?

## Tool Box...

What does the term Tool Box mean as used with Maple?

## How do I create a function using define_external?...

Hi! I have an external library with this function: ``` double test(double x) { return sin(x); } ``` In Maple I am doing this: test := define_external('test', x::(float[8]), RETURN::(float[8]), LIB = "Test.dylib"); f := x->test(x); Now when I call f(2) for example, I get 0.909297426825681710 back. But if I try this: plot(f(y), y = 0 .. 2); I get this error message: `Error, (in f) invalid input: test expects its 1st argument, x, to be of type numeric, but received y` I think I need to somehow convert the (possible) symbolic input of f into a float[8] before it is passed to the procedure test, but I can't figure it out.

## Plotting surfaces in Maple with constraints...

Dear All, Does anybody know how to plot a surface in 3d with only those points which satisfy a constraint? In particular I'm plotting the surface defined by the equation F(beta,Omega,delta)=0 using implicitplot3d. Unfortunately, I want to command Maple to leave out any points which violate the inequality h(beta,Omega)>0. Does anybody know how to do this? cmichael

## Enumerate all minimal cut sets in the graphs...

Hello, I have expressions of the form `e[i,j,k]:= s*U(s)*a(s,y,z,t)+ s*(s+1)^2*b(s,y,z,t)+ ...` where `e` is a symmetric array, i=1..4, j=1..4, k=1..4 and function a(s,y,z,t),b(s,y,z,t),c(s,y,z,t),f(y,z,t),g(s,y,z,t),... and their partial derivatives are appearing in these expressions I exracted different coeff, named them, and then I wanted to rewrite each e[i,j,k] while substituting coeffs with implicit function, so I've used `applyrule` in a procedure but not all coeffs are substituted. Can anyone help please. Here is my worksheet View 4780_beny1.mw on MapleNet or Download 4780_beny1.mw