## Plotting multiple curves...

Hi! I'm trying to plot a graph of (u^2/sin^2(k))-(v^2/cos^2(k)) where the value of k varies. i've found the kind of command that plots multiple lines on the same graph: plot({seq((x-k)^2,k=0..5)},x=-10..10); but am not sure how to change it to produce a graph with multiple lines on for my function which has both u and v that vary. Thanks

## Animation of Archimedes Screw....

Hi I need to animate the Screw of Archimedes using maple, I tried animate3d and insequence=true and both don't work. This is the screw. plot3d([a*cos(x),a*sin(x),3*x],a=-15..15,x=1..8*Pi,axes=framed,scaling=constrained,color=gold,numpoints=4000,style=patch); This is the center cilinder. with(plots):plot2:=implicitplot3d([x^2+y^2=40,z],x=-15..15,y=-15..15,z=1..24*Pi,axes=framed,color=yellow,numpoints=5000); I should also make a function that "lays" on the screw, and a point should be visible going upwards, this should make the water that gets pumped up by the rotating move.

## pointplot series of curves...

Need help pointplotting series of curves. thanks, TL

I have a long file and i would like to only pick up some parts to run sometime. Does anybody know how to change multiple commander lines to miltiple comment lines? What i know is that # can change one commander line to comment line. Thanks a lot!

## How to... generate indices of a selected subset of...

Hi, all! Perhaps this is an obvious question for experienced users, but it's given me some trouble as a newbie... many thanks for anyone who can help me with this... I'm trying to find a way to return the indices of a selected subset of an array (or matrix, or whatever, I'm not picky.) Here's a simple example of what I'm talking about. Here's some actual Maple input/output that I ran:
```> foo := Array( 1..10 , i -> i ) * 2;

foo := [ 2 4 6 8 10 12 14 16 18 20 ]

> bar := select( x -> ( x mod 3 = 0 ) , foo );

bar := [ NULL NULL 6 NULL NULL 12 NULL NULL 18 NULL ]```

## Integro-Differential Equations...

This is my system: rho * diff(diff(delta(x, y, t), t), t) = (y ^ 2 / 0.2e1 - d ^ 2 / 0.8e1) * Y * diff(diff(diff(diff(xi(x, y, t), x), x), x), x) + (((2 * G + lambda) * v - lambda) * diff(diff(xi(x, y, t), x), x)) + 0.16e2 * Q(t) ^ 2 * y * (d ^ 2 - 0.2e1 * y ^ 2) / d ^ 4 / b ^ 2 / l ^ 2 / e; diff(delta(x, y, t), y) = v * y * diff(diff(xi(x, y, t), x), x); i = 0.8e1 * Df * Q(t) / d ^ 2 + l * Lp * (int((2 * G + lambda * (v - 1)) * diff(diff(xi(x, y, t), x), x), x == (0..b)) + Y * d ^ 2 * int(diff(diff(diff(diff(xi(x, y, t), x), x), x), x), x == (0..b)) / 0.12e2) + diff(Q(t), t); My objective is to obtain the expression of delta,xi and Q to the space coordinates(x,y) and time,t.The other letters are constants. Can the maple do this? I try with pdsolve but obtain this error:

## Reduce number of arguments of a given function...

I have a function with two arguments and want -- as the first argument gets fixed -- to transform it to a function with just one argument. The difficulty is that I use for the function definition the same symbols as in the worksheet where those symbols are assigned to numerical values. The main problem is, as the following minimal example shows, that the variable A is not evaluated during the definition of function g(). ``` > a:=1: > b:=2: > f:=(a,b)->a+b; (a, b) -> a + b > A:=3.5: > g:=b->f(A,b); b -> f(A, b) > g(0); 3.5 # O.K. > A:=4: ```

## How to specify the digits of a Matrix element...

I want to creat a Matrix A with every emement in A Digits:=20,How can I do?A:=Matrix(n,n,?) waiting for your help!

## Matrix algebra...

Hello, I have a simple problem of the type; x = L(x)*x Where x is a column vector (2) and L(x) is a 2 by 2 matrix (function of x). I want maple to solve this equation for x. I just don't know what is the function to do this ("solve" doesn't work).

## excel to maple10...

how can i import data from an excel spreadsheet into maple10? (please don't tell me i can only to it with maple11). cheers, jake

## Paths in a directed graph...

Hi, I am using the networks package to try to find out the total number of paths between two vertices of a graph. The graph I am interested in is basically a square grid with a diagonal from the lower left to the upper right. I want to find the total number of paths from the lower left vertex to the upper right vertex according to the following rules. 1. Can only move right 2. Can only move up 3. Can only move up the diagonal. So I wrote a procedure that would produce such a directed graph for any n. For any n the graph has n^2 vertices but only edges that meet the criterion given above.

## Numerical integration in M11 vs M10...

I have a sheet in Maple 10 which I want to re-run in Maple 11. It contains a very lengthy (piecewise defined) function f(m) to be integrated over the Reals (numerical) and dito for exp(m)*f(m). The results are certainly ~ 1. In M10 this caused problems which can be overcome using method= _NCRule (I got the advice here ...) in both the cases, the result came up fast. In M11 I killed the execution, it needs to long. While integrating f(m) can be done by the NAG routines, that does not work for exp(m)*f(m). Certainly I could split up at the breaks for piecewise - but can somebody explain *why* it 'fails' now? And: no, I do not want to split up manually.

## How do I do a double loop?...

Set up a double loop in maple with the parameter "a" runing from 0 to 2 in steps of 0.02 and b running from -1 to 1 in steps of 0.02. Within de double loop set, set X0=a+b*I and compute 10 Newtons iterates. If X10 is close to 0, say absolute value of X10<0.1 then the iterates converge to 0. Color the pixel at (a,b) black if the iterates converge to 0 and white if not.
"Note": The equation to be set is X^3-3*X^2+2*X
Please help me in here, is due to tomorrow, and I've been trying all this week but I don't have any clue.
Best Regards,
Franklin...