## ODE Analyzer...

I am using the ODE analyzer to look at the numerical solution to a second order ODE of the form 0=-uc'-kc+Ec" with u=.3, k=.0001 and E=10, and with conditions, c(0)=2 and c'(20,000)=0. When I try the solve numerically, I get an error message saying "unable to convert input to a first order system. Recieved error: too few boundary conditions, expected 5 got 2." What am I missing?

## solving PDE's...

I am trying to solve the following system of PDE's
dn := diff(n(x,t),t) = d*diff(n(x,t),[x,x])+n(x,t)*(r(n(x,t)+m(x,t)))*s(C(x,t))-n(x,t);
dm := diff(m(x,t),t) = d*diff(m(x,t),[x,x])+m(x,t)*(r(n(x,t)+m(x,t)))*s(C(x,t))-m(x,t);
dc1 := diff(C(x,t),t) = d*diff(C(x,t),[x,x])+P+(n(x,t)+m(x,t))*p(n(x,t)+m(x,t))+H*m(x,t)*p(n(x,t)+
m(x,t))-(P+p(1))*C(x,t);

with initial and boundary conditions
IBC := n(x,0)=piecewise(x^2<1,0,x^2>1,1),m(x,0)=piecewise(x^2>1,0,x^2<1,1),C(x,0)=1,
C(infinity,t)=1,n(infinity,t)=1,m(infinity,t)=0,n(-infinity,t)=1,m(-infinity,t)=0,

## accessing lists...

I have made some lists named K[i], i= 1 to 48, with matrices, but this doesn't make maple happy, and I get 'Error, invalid subscript selector'. The problem is obvious that K[i] is taking element i in the list K, and I get problems when I want to take list K[i] and look at element j. So, how do you give lists names with indices?

## Show substitution values in Maple11 Tutor Integrat...

When Tutor suggests a 'change in variables' and next step is applied, is there a way to get Tutor to show the substitution for variable u as well? thanks

## Fixing display of math (gifs from MathML) in maple...

This is a new user question. mapleTA3.01 is installed on an Ubuntu linux server here at maths.uwa.edu.au and on SUSE linux at maths.curtin.edu.au across the river here. We have classes (around 1000 students at each institution) about to start soon and have been forced by the maple vendor to switch from AiM to mapleTA. (And, no worries, we will try. The March start date is scary.) We are having problems with most maple-type questions, displaying maths. Intermittently, the gif for the maths does not seem to get written. These are from the maplesoft Calculus questions. It isn't in anything peculiar

Hi, I have two questions, which should be relatively simple to solve. First of all, how do you name the axes in a plot? Second, how do you change the dimensions of a spreadsheet in maple? For example, if I wanted a 500 by 2 spreadsheet, how would I go about getting it? Right now the spreadsheet maxes out at 100 rows Thanks for your help -Evan

## Retrieving index of a variable...

Hi how can i retrieve the 1 in x in a maple program or 2 in y?

## How do you delete the DLL's generated by Compiler:...

I have a program that may call Compiler:-Compile to speed up the calculations, but after the program terminates the DLL that was generated still exists on disk. Every time I call on the program, I create a new DLL without deleting it. If I keep calling my program, the disk will get full of temporary DLL's until the disk gets full. I know how to delete using FileTools:-Remove, but I get the "permission denied" error message. I assume that it is because Maple 10 is still using the DLL, so how do I get Maple to free the DLL so that I can delete it?

## Multiple Point Plots on Same Display, Select Line ...

Suppose I have the vertices of a polyhedron in a matrix and wanted to draw a stick model of it as a plot. I need to be able to specify the color of each edge. What's the best way to go about this? I've tried creating an array of pointplot3d's with connect=true and grouping them together with the display command but that doesn't seem to allow me to select colors for each edge. As an example, if you could show me how to make a line from

All: I am comparing examples of Lower Sums, Upper Sums, and Random Partitioned Riemann Sums. For the lower and upper sums, the leftbox and rightbox commands produce satisfactory box shading results, green RGB(.7,.9,.7). For example: leftbox(x,x=0..2, 4); However, I can't get the RiemannSum command to shade. I have used all of the tricks that I know of and all that I can do is change the color of the outline of the boxes. For example: RiemannSum(x, x = 0..2, partition=2, method=lower, output=plot, showarea=false, outline=false, boxoptions=[color=black, thickness=2], thickness=3, title="", tickmarks=[5,6], labels=["",""], scaling=unconstrained, refinement = random, functionoptions = [legend="", color=RED], partition=random[.75]);

## how to evaluate faster?...

I need to evaluate expression

sum((sum((sum((1-p)^i/(a*i+a+a*j+a+a*k+a), i = 0 .. infinity))*(1-p)^j, j = 0 .. infinity))*(1-p)^k, k = 0 .. infinity).

A straightforward evalf(subs(a = .4, a = .1, a = .5, p = 1/3, %)) is too too slow. Are there any faster solutions? Thanks in advance.

## How do I make an underscore in Maple?...

Every time I try to make an underscore _ in Maple, I am forced into a subscript. Hence, I cannot enter commands such as dperiodic_sols from the DEtools list into my program. Thank you.