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From: jmonroy@netcom.com (Jesus Monroy Jr)
Subject: Food for thought
Message-ID: <jmonroyCBssIJ.3rp@netcom.com>
Keywords: logic permutations combinations factorials
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Sun, 15 Aug 1993 11:13:31 GMT
Lines: 74
Some Formal Logic... try it!
----------------------------
Legend
------
A first proposition
B second proposition
-> implication
~ Not
T True
F False
A | B | conclusion | | Inverse |
| | A -> B | | ~A -> ~B |
----+-------+ +----+ | +-----+
| | | converse | | Contrapositive
A | B | | B -> A | | ~B -> ~A
----+-------+-------+-------+--+----+-------------
| | | | |
T | T | T | T | T | T
| | | | |
T | F | F | T | T | F
| | | | |
F | T | T | F | F | T
| | | | |
F | F | T | T | T | T
-------
Permutations
------------
If "M" denotes the number of permutations of "n" things
taken "p" and at time, --
M = n(n-1)(n-2).....(n-p+1).
-------
Factorials
----------
-n n
n! = e * n * square_root(2 * pi * n), approximately.
-------
Combinations
------------
If "M" denotes the number of permutations of "n" things
taken "p" and at time, --
M = n(n-1)(n-2).....(n-p+1) / p!
or
M = n! / p! (n-p)!
-------
If you've found an error please write to me.
jmonroy@netcom.com
___________________________________________________________________________
Jesus Monroy Jr jmonroy@netcom.com
/386BSD/device-drivers /fd /qic /clock /documentation
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