Suppose I generate a PLOT3D structure by
p:= plot3d(f(x,y),x=-1..1,y=-1..1,grid=[3,3]):
p2 := convert( p, POLYGONS );
Now I want to go through these polygons and throw away those that have a vertex far away from the origin (say more than 10 units), and then redisplay the trimmed structure.
Is there a snazzy way to do this?

Maple needs commands to interpolate and plot large data sets. Consider the following:

# generate data
data := convert(LinearAlgebra[RandomMatrix](10000,2,generator=-100000..100000),listlist):
data := sort(map([op], [op(op(table(map(`=`@op, data))))]), (a,b)->evalb(a[1] < b[1])):
data := Matrix(map(proc(a) [a[1],a[2]/200.] end,data), datatype=float[8]):
# now suppose I take this data and...
f := CurveFitting[BSplineCurve](data, x);
plot(f, 0..100);

Someone trying to do this with real data (and 10000 points is small) will experience the following problems:

1. When Maple exports its worksheet to LaTeX, it converts each plot to an .eps file with /drawborder set to true in the .eps file as a default. I have found no information or a preference in Maple 10 that would allow me to change that default to false. Is there a way to change that default in Maple to false? If not, is there a way in a TeX file later to change that switch to false so that .eps figures drawn with \includegraphics command would appear without a border? I know I can open any .eps file in say MS Notepad and manually edit the line /drawborder true to /drawborder false, but I am looking for a smarter way to do that.

I am using Maple to solve some inequalities where the solution I get is a RealRange or a real constant. And I want to get an union of these values. I wrote a short procedure which does the work. But is there a better way to do this (there must be :-) )?
```
> RealRangeUnion:=proc(L::list) local L2, rel, rel2, eq, sol, x;
> assume(x, real);
> L2:=map(a->`if`(a::realcons, x = a, x in a), L);
> rel:=convert(L2, relation);
> rel2:=convert(Or(op(rel)), relation);
> eq:=piecewise(rel2,1,0);
> sol:=solve(1=eq,x);
> RETURN(sol);
> end proc:
>
> L:=[RealRange(Open(-2),-1), RealRange(Open(0),1), RealRange(1/2,2), -3, -2];
```

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)

Greetings. As mentioned in earlier posts, I often find the answer given to a question regarding the use of the 'sum' command as: don't use 'sum', use 'add', and all will be fine. I agree, and I use the add command for adding numbers together. But, if all I am doing is adding numbers together, from a sequence and nothing else, why not use the 'sum' command. It seems to be orders of magnitude faster than the 'add' command if there are a large number of numbers(I have no metric for what large is as far as numbers go). As an example, I execute the code below and look at the results.
> restart:

I am using the latex2edu conversion service at
qa.brownstone.net/latex2edu
to convert latex files into MapleTA questions.
However, for the last 4 days this service has not been available.
Mail to support@brownstone.net and my local MapleSoft representative has not been answered.
Has anyone else experienced this problem?
Does anyone know whether the service is available elsewhere?
Arne Jensen
Aalborg University
Denmark

Hi,

we've been happily using Brownstone's latex -> edu conversion service for some time now, but always with that slightly queasy feeling of "what happens if it's unavailable?". Well that's the case at the moment: I've submitted a ticket with their support folk, but times in Australia don't match up well with US times! In the meantime we have a number of assignments due to be made available to students, but which only exist as latex files. Conversion by hand is, to say the least, painful and time consuming (our Level I coordinator has already converted two by hand, and doesn't need another few hours of such nonsense), so I'm hoping that there may be another way in which this can be done. Any suggestions?

Hello,
I would like to use Maple instead of Matlab, well I rewrite the Matlab code to Maple like following. The output is correct, but it spends more time than in Matlab. Is it possible to rewrite my Maple code to get output faster?
```
restart:
linearni_model:=proc(beta,sigma)
local n1,n2,Y,X,Y1,Y2,se,se2,t1,t2,t3,t4,vbeta,t,si2,e1,e2,e3,e4,Yp,N,s2,n;
use Statistics in
X:=Matrix([[1, 1, 1, 1, 1], [1, 1, 1, 1, -1], [1, 1, 1, -1, 1], [1, 1, 1, -1, -1], [1, 1, -1, 1, 1], [1, 1, -1, 1, -1], [1, 1, -1, -1, 1], [1, 1, -1, -1, -1], [1, -1, 1, 1, 1], [1, -1, 1, 1, -1], [1, -1, 1, -1, 1], [1, -1, 1, -1, -1], [1, -1, -1, 1, 1], [1, -1, -1, 1, -1], [1, -1, -1, -1, 1], [1, -1, -1, -1, -1]]);
```

Would anyone be able to help me integrate ones like the following:
Int(1/exp(eta)*eta*hypergeom([1, 1, 1],[2, 2, 2],eta),eta);
I've tried using convert, simplify, etc. but nothing works.
Many thanks,
Sandra

I used Maple10 to solve an ODE from my research project and got a solution with HeunC function. I did derivative of the HeunC function and got HeunCPrime function. However I found HeunCPrime is just a sign. It cannot be valued or plotted with a selection of parameters. My questions are as follows:
1. Is there any special package I need to use to value or plot HeunCPrime function?
2. Is it possible to convert HeunC into other functions which I can manipulate for derivative and plotting?

Hi,
I've been experimenting with the quaternionspackage. (The free download, not the commercial package). There seems to be an error in the calculation of the inverse:
with (Quaternions);
[*, +, -, Qabs, Qadd, Qamplitude, Qangle, Qarccos, Qarccosh, Qarccot,
Qarccoth, Qarccsc, Qarccsch, Qarcsec, Qarcsech, Qarcsin, Qarcsinh, Qarctan,
Qarctanh, Qargument, Qaxial, Qceil, Qcolatitude, Qconjugate, QconvertToFrac,
Qcos, Qcosh, Qcot, Qcoth, Qcsc, Qcsch, Qdefine, QdivLeft, QdivRight, Qdot,
Qeval, Qexp, Qfloor, Qfrac, Qicoeff, Qinverse, QisCommutable, QisEqual,
QisPure, QisScalar, Qjcoeff, Qkcoeff, Qlength, Qln, Qlongitude, Qmagnitude,

Hi
I have the following maple file. Is anyone able to convert the maple code of the calculation of the reflected lines to the simple mathematical steps which are used to calcualte it.
The calcualtion of the outgoing ray is from:
if (abs(dr) > 0.001) then # if slope = 0 no outgoing ray
> m := (dr^2 - 1)/(2 * dr):
> ix := (height - y)/m: #
> if ix <> tx := -width:
> ty := y + m * (tx - x):
> elif # Calculation of outgoing ray
> ix > width then #

Is there a package available in Maple that converts between number systems ?
e.g., binary, octal, hexadecimal.
v/r,

How do I get Maple to convert the output of the polar() to degrees with convert(arg, degrees)???
Does the polar() store the magnitude and angle values that is spits out into some variable somewhere that isn't documented? I can't figure this out right now; short of making a copy of the angle part of the polar()'s output to then be fed back into the convert(angle, degrees) statement.
Help anyone?