restart; interface(version);

    Classic Worksheet Interface, Maple 12.00, Windows, Apr 10 2008 Build ID 347164

  Int(1/(u^2+1/4)*exp(I*u*k),u=-infinity...infinity); value(%);

                                  0

but

  Int(1/(u^2+1/4)*exp(I*u*k),u=-infinity...infinity...

[I am using Maple 12.01 with Windows XP].

I tried to use gfun[listtorec] to find a recurrence for a particular sequence (given below), but the recurrence found is not correct.
Yet,  guessgf apparently gives the correct generating function.

>with(gfun):
>L:=[5, 8, 14, 24, 42, 72, 126, 216, 378, 648, 1134, 1944, 3402, 5832, 10206, 17496, 30618, 52488, 91854]:
>rec:=listtorec(L,u(t));
               [{-u(t + 2) + 3 u(t), u(0) = 5, u(1) = 8}, ogf]
 

For the last couple of weeks, I’ve been flying around the world on a press tour … sounds glamorous doesn’t it? Images of Brad Pitt or Prince William come to mind? Well, any similarities between a Brad Pitt press tour and one that I’m involved in is purely coincidental (if not miraculous). So what does one do on a Maplesoft press tour?

 Well, as it turns out, there actually is a fairly active community of journalists from far and wide who have a particular interest in recent developments in engineering and mathematical computing. And every year or so, we like to meet the press face to face to keep the lines of communication open between the company and these influential people of letters. This year, my tour took me through key regions in the US, UK, and Germany.

It looks like `forget` works on procedures with option 'cache'.

I realize that there is a routine Cache:-RemovePermanent. But should `forget` be clearing the permanent Cache entries for a procedure?

> cacheFunc := proc() option cache; print(args); args; end proc:
> Cache:-AddPermanent( cacheFunc, [5], 10 );
> op( 4, eval(cacheFunc) );
                      Cache(512, 'permanent' = [5 = 10])
 
> forget(cacheFunc);
> op( 4, eval(cacheFunc) ); # NULL return, it's empty

One of our TAs reported this to me earlier today. (A student reported it to him.)

Sum(sin(1/10000.0*i^2), i = 0 .. 199):
%, value( % ), evalf( % );
            199                                                   
           -----                                                  
            \                                                     
             )      /                 2\                          
            /    sin\0.0001000000000 i /, 80.85387129, 127.2891137
           -----                                                  
           i = 0     

The student used evalf. I suggested that value was a better first option in this case. Since this is just the sum of a fixed set of numbers, an even better alternative is to use add:

add(sin(1/10000.0*i^2), i = 0 .. 199);

                                 80.85387132

The problem disappears when Digits increases to (at least) 15.

The following example was shown to me by Matthias Kawski.

He noticed a difference in the way Maple 12 handles some definite integrals from the way they were done in Maple 8. Both cases point out some problems. I'll offer my explanation of the problem after I show what Matthias observed: First, the results from Maple 8. Each of these 4 examples evaluates a definite integral in two different ways, the first using a function and the second using an expression. All looks fine until the last example.

Hi there ! The attached worksheet has a good review on the theory of Limits and Continuity of functions that have two or more variables.

The attached worksheet has a specially designed tool that helps you evaluate the limits of really complicated multivariable functions.

Please feel free to ask questions.

Limits_and_Continui.mw

For a single pair of left single quotes, ?name is clear:

Any valid Maple name formed without using left single quotes is precisely the same as the name formed by surrounding the name with left single quotes.

So this is fine:

`x`;
                      x

But what about multiple left single quotes? This help page also states:

If you have a standard math, complicated expression in your Maple worksheet that you would like to include in a blog in this venue, what's the most economical way to copy & paste it?

Alla

Maple gives different error messages to the same input depending on whether the input is done with Maple notation or 2D Math Input.

My example is to enter the following erroneous input in both Maple notation and 1D math notation:

plot( sin(x, x=0..1 );

Clearly this is missing a right parenthesis after the first x.

Here is how this section of my worksheet copies into MaplePrimes:

I find that for some plots the choice of location for tickmarks and axes labels in the Classic version is better than the Standard one. Eg. here:

with(plots):
complexplot3d(sin(z), z=-Pi-1.5*I..Pi+1.5*I,axes=boxed,
style=surfacecontour,tickmarks=[[-Pi=-Pi,0=0,Pi=Pi], 
default,default],orientation=[72,49]); 

Classic:

Okay, so September ended last week...but I am awake.

Seeing as we came to the end of another quarter (and this time I noticed it on time), we have to awards to distribute this month: 

How many arrangements of the word GELATINOUS are possible if the vowels must always be in alphabetical order?

Could MaplePrimes be made a little more robust?  It seems that roughly once a month I get a Drupal error all weekend instead of access to MaplePrimes.  I frequently have more time on the weekend to answer some questions, so it is the community that loses when the site is down... 

This has now happened frequently enough that clearly there is a systemic problem in the infrastructure, and it would be nice to know that it is being investigated and fixed.

When inserting standard math into a text region, Maple insists on converting even simple decimals like 0.01 into scientific notation.  Can I suppress that?

Allan