My Calculus III students stumbled on this buggy thing while evaluating a line integral to calculate the flux The curve [X(t),Y(t)] is the right-half of a Lemniscate with polar equation R^2=cos(2*theta). The vector field is F(x,y)=M(x,y)i+N(x,y)j. They were integrating M*dy-N*dx around the curve. If we let a=M*dy and aa=expand(M*dy), then they find that Maple's int gives inconsistent results. As far as I can tell, a and its twin aa are well-behaved over -Pi/4..Pi/4 and equal. Maybe it is a bug in how Maple handles elliptic integrals? Or maybe it is some issue with removable discontinuities?

We are pleased to announce the winners of the monthly Maple Mentors Awards for October and November. The winner for October is Douglas Meade and Georgios Kokovidis has won for November. Douglas Meade and Georgios Kokovidis will receive a prize of their choice to thank them for their involvement with the MaplePrimes community. We have received many emails nominating these individuals. One member had this comment concerning the help given by Douglas Meade:

I was writing a small procedure to generate random points on the unit sphere. The details are not directly relevant here, but the procedure was as follows.

randspherepts := proc(n::nonnegint, d::posint) 
 local i, p, r; 
 description "Returns co-ords of n random pts on the d-dimensional unit sphere [Knuth, 1998: sect. 3.4.1E]"; 
 uses ArrayTools;
 p:= Matrix(n, d, RandomTools:-Generate('distribution(Normal(0,1))', makeproc=true),datatype='hfloat',order='C_order');
 r:= ElementPower(AddAlongDimension(ElementPower(p,2),2),1/2);  
 seq(ElementDivide(p[i,1..-1],r[i]), i=1..n) 
end proc;

Using MAPLE V, Release 11, a creep curve has been formulated, which represents the mechanical behavior of metals, polymers, and ceramics, for instance.

Inspired by the post Re: the physics package I decided to have a closer look at the function FeynmanDiagrams. As the Lagrangian I thought I might as well take the QED Lagrangian for a massless spinor field Q[i](X) coupled to an external electromagnetic field A[mu](X):

restart:
with(Physics):
Setup(advanced):
L_QED :=
   +Dagger(Q[i](X)) * Dgamma[4] * Dgamma[mu][i,j] * I * diff(Q[j](X),X[mu])
   +Dagger(Q[i](X)) * Dgamma[4] * Dgamma[mu][i,j] * e * A[mu](X) * (Q[j](X));

Can someone explain why is 0 handled differently by evalf[10] than nonzero numbers in the following examples? Digits:=50: epsilon:=Float(1.0,-30); -30 1.0 10 for x in [0,0.0,1,sqrt(2),Pi] do x,evalb(evalf[10](x)=evalf[10](x+epsilon)); od; 0, false 0., false 1, true (1/2) 2 , true Pi, true

In trying to answer the second question in How to determine the order of an ODE? I have unsuccessfully tried to use select to filter out the appropiate parts of the differential equations. In these attempts I have hit upon a behaviour of select I do not understand: In my opinion each of the following two code lines (or at the very least the second line) should return the differential expression itself:

select(has,diff(y(t),t),y);
select(has,diff(y(t),t),y(t));

But they do not; each line returns diff(y(t)), where the variable t with respect to which is being differentiated is missing. Why? Is it just me having fundamentally misunderstood something?

So what is the best way to put a "link" from one place in a maple document to another. So that someone can jump quickly when clicked? Thanks!

I recently changed the system from 10.4.10 to 10.4.11 and not too long afterwards noticed the following problem: when I restart my machine the maple 9.5 does not load properly. It takes about three restarts to get maple to open. Any suggestions?

The following is the code for the 2nd Fick's law with initial/boundary conditions. Unfortunately this code does not show me the result required for next process. It would be useful for us to proceed this work. Thanks in advance. ( Currently we are using Maple 10.) > restart; > DiffusionCoefficientST := 0.5e-2; > ExperienceConstant := 5; > Temperature := 273+25; > PDE := diff(C(x, t), t) = > DiffusionCoefficientST*(exp(1))(-ExperienceConstant(1/Temperature-1/296))*(­diff(C(x, > t), x, x)); > IBCondition := {C(x, 0) = 2, C(0, t) = 0, ((D[1])(C))(5, t) = 0}; > pds := pdsolve(

Maple 11 has been working flawlessly for me under Mac OS X Leopard, with both updated. However, while the screen output appears to be fine, the Times New Roman (and other?) fonts seem to disappear and are replaced by a sans serif font (like Helvetica or Geneva). This occurs whether I send the output to a postscript laser printer (HP 2200) or to a non-postscript inkjet (HP 5550). I vaguely remember having a similar problem years ago, i.e., prior to Mac OS X. Has anyone else encountered this problem? Has anyone who encountered this identified a solution? So far, I'm stuck exporting my resu

I hope someone can shed so light on the following: I upgraded to SuSE10.3 -32bit recently and everything seemed to go well. Maple 11.01 was installed and has worked fine until now. Today was the first time I tried to print a file and 'Lo and Behold. There is no print function at all! Whenever 'Print' or 'Page Setup' is clicked there is a brief moment of 'wait' cursor and then nothing happens. No dialog box, no warnings just silence. I did a search for similar issues on Google but came up empty. I've checked the CUPS config file for the Linux fix regarding Sockets, that made no difference, I checked the installation of CUPS and it seems fine, indeed, every other application prints fine. By the end of the day I resorted to reinstalling Maple and that didn't make any difference either. I'm at a loss. Anyone using SuSE and Maple 11.01 care to comment?

For a long thread it is often a bit difficult to locate the new posts referred to in the Replies column of recent posts, especially if the thread has laid dormant for some period of time over which its detailed history has been forgotten. Therefore, could new posts be highlighted in some way to make them stand out?

This is a follow-up on one of the unresolved issues raised in a previous post of mine. In view of the fact that 1 + I is indeed of type complexcons, can anybody please explain why the following is reasonable:

restart:
assume(x::complexcons):
evalc(x + conjugate(x)),
evalc(x - conjugate(x));
restart:
x := 1 + I:
evalc(x + conjugate(x)),
evalc(x - conjugate(x));
                            2 x~, 0
                             2, 2 I

Would someone try the Integration Tutor with csc^3(x). On SuSE Linux 10.3 with maple 11.01 it just loops through the Parts rule. Endlessly it seems. Worksheet works fine though. Tim