Doug Meade



Douglas B. Meade <><
Math, USC, Columbia, SC 29208 E-mail:
Phone: (803) 777-6183 URL:

MaplePrimes Activity

These are questions asked by Doug Meade

What tools are available to help with the search for syntax errors within Maple code? It seems to me the built-in debugger is designed to assist with the testing of Maple code with no syntax errors. While this is important, and useful, the code has to be syntactically correct before this is of any use. Here's the situation I am facing. I have a file with more than 3500 lines of Maple code. Close to 1000 lines is the definition of a maplet, which has to be in one execution group. If there is a single missing comma, square bracket, or parenthesis, Maple will generate an error message and will place the cursor somewhere within the offending execution group. I have seen enough error messages that I know what they mean; I'm not complaining about the error message. My complaint is about the location of the cursor. While the location is deterministic, it is rarely close to the actual location of the error. Does anyone have any useful tips for how to locate the source of syntax errors within large Maple programs?
A colleague just asked me what Maple would do if asked to solve an equation in which the right hand side is infinity. I didn't really know what it would do, so we did some tests:
f := (x-1)/expand((x-1)*(x+1)*(x-2)):
solve( f=infinity, x );
                                    1, -1
solve( 1/f=0, x );
                                    2, -1
solve( denom(f)=0, x );
                                  1, 2, -1
I could not explain the response to the first solve command. Can you? Thanks in advance, Doug
A colleague recently approached me with this problem: Given two sets S1 and S2 in R^3, define the "product ball" of S1 and S2 to be the set of all points in R^3 obtained as the componentwise product of a point in S1 and a point in S2. That is, PB(S1,S2) = { (a*x,b*y,c*z) : (a,b,c) in S1 and (x,y,z) in S2 }. Can Maple help me to visualize this set? For a concrete example, let S1 = { (x,y,z) : max( abs(z), abs(x)+abs(y) ) = 1 } and S2 = { (x,y,z) : max( abs(y), abs(x)+abs(z) ) = 1 } In this case it can be shown that PB(S1,S2) consists of the following eight parametric surfaces: (x,y,z) = ( s*t, 1-s, 1-t), s=0..1, t=0..1
I know I have done this before, but I'm not having any luck today. I am using Maple 10. I want to check if a user-entered function is positive for values in a bounded or unbounded interval. I do not want to do too much that is fancy, just functions that are likely to show up in the integral test for convergence of a series. Specific question: How can I get Maple to report that 1/sqrt(k) is decreasing for all k>1? I have tried working with both sqrt and surd, and with various assumptions. But, nothing gives a useful result.
f := 1/sqrt(k);       # no information
solve( diff(f,k)
I want to display international characters in maplets. For this to work with the MapletViewer I have found that they maplet needs to be saved using the Western (Windows-1252) encoding. (Even this appears to not be entirely perfect, but that is not the issue here.) I have had absolutely no success with MapleNet. The international characters appear differently when the same maplet is launched with MapletViewer and with MapleNet. The two maplets can be viewed from our MapletNet server by visiting the URLs:
1 2 3 4 5 6 Page 5 of 6