unfortunately not, I don’t know anything about the specifics of the HD decoder.

only a pleasure – glad I could help.

on line 3, I rewrote both sides of the equation, but didn’t actually perform any calculations.
On the left, (a^2)-(b^2) can be written as (a+b)(a-b), since if you multiply that out you get (a^2) -ab + ab -(b^2). -ab + ab is 0, so you get (a^2)-(b^2)
On the right, ab-(b^2) has b common to both ab and b^2, so the b can be factored out and the line written as b(a-b). If you multiply b(a-b) out you get ab – (b^2).

In both cases the lines are rewritten in a different form without any calculation being done.

http://en.wikipedia.org/wiki/Mathematical_fallacy

very interesting though

How do you get:
(a+b)(a-b) = b(a-b)

From line 3? If you divide ‘b’ from the right side of the equation, you must do the same on the left, giving you:

( (a^2)-(b^2) /b) = b(a-b)
simplified: (a^2)/b) – b = a – b
Eg replacing with #’s
4/2 – 2 = 2 – 2

Was the answer faulty math? XD

I’m running GNU Emacs 23.1.1 on Windows XP. I’m running a single ack.pl file, version 1.94 – I have ActiveState Perl installed and set up to execute .pl files, and I placed ack.pl onto my path.