http://forum.swarthmore.edu/dr.math/problems/m.for.slope.html
for the discussion about using m for slope. I contacted Ken Williams who
runs the page and he gave me permission to copy what's there to this list.
He did note that things get added all the time, so readers may want to
visit the site too.
Here's the current text on the above mentioned web page. It's interesting
to see a name like John Conway (creater of the Life computer simulation
among many other things) there, though I've seen him on other lists in the
past.
Phil Mahler
Middlesex CC
Bedford, MA
------------------------------------------------------------------------
Why m for Slope?
Date: ed, 9 Nov 1994 15:44:42 -0800 (PST)
From: Mary Koch <marykoch@cks.ssd.k12.wa.us>
To: dr.math@forum.swarthmore.edu
Dr. Math:
My class wants me to ask you why the letter m was selected to
represent slope.
Mary
Date: Sat, 12 Nov 1994 07:28:39 -0500
To: marykoch@cks.ssd.k12.wa.us, dr.math@forum.swarthmore.edu
From: steve@forum.swarthmore.edu (Stephen Weimar)
Subject: Re: why "m" for slope
>Date: Fri, 11 Nov 94 23:47:50 EST
>Sender: nctm-l@sci-ed.fit.edu
>From: EVOOLICH@mecn.mass.edu
>Subject: Re: why "m" for slope
>
>Why call slope m has been a question that has been researched by
>math historians but has not been answered definitively yet. All
the
>usual suggested "reasons" have proven false. One math historian
has
>been doing a search for a few years for the earliest use in a math
book.
>So the jury is still out on this question.
>
>Erica Voolich
>evoolich@mecn.mass.edu
__________
From: "John Conway" <conway@math.Princeton.EDU>
Date: Sun, 13 Nov 94 19:38:58 EST
To: rfoster@unm.edu, steve@forum.swarthmore.edu
Subject: Re: why "m" for slope?
Cc: geometry-pre-college@forum.swarthmore.edu
I believe (but am not sure) that what we now call just the
"slope" was once called the "modulus of slope", the word
"modulus" being used in its sense of "number used to
measure" (as in "Young's modulus").
Descartes' "La Geometrie" doesn't use the "m" in this
connection, but I seem to remember that Euler often does.
Descartes makes no use of Greek letters for parameters in
his Geometrie, and most later authors have followed him in
this, if we except the use of theta, phi for variable
angles.
This is an interesting question - I'll try to track it back.
John Conway
__________
Date Mon, 19 Feb 1996 08:52:40 -0500 (EST)
From: John Conway <conway@math.Princeton.EDU>
Subject: Re: GEOMETRIC TERMS
When this question came up last year, it emerged that many
people have been taught that it comes from the French, "montrer",
to climb. I think this is an "urban legend".
I don't have much faith in the theory I put forward then -
that this m stands for "modulus of slope". It is true that
the term "modulus" has often been used for "the essential parameter
determining".
John Conway
__________
Date: Mon, 19 Feb 1996 10:07:33 -0500
From: Andr Desch nes <adeschenes@qui.qc.ca>
Organization: Le Petit S minaire de Qu bec
Subject: Re: GEOMETRIC TERMS
I recently met a former Mathematics book writer, M. Risi, who wrote
some books for teaching mathematics at a level that is about the
same as pre-college. These books where written in French for
students of Quebec province. I asked him exactly the same question
as yours: "Why did you use m for slope? No French word
beginning with the letter m seems to me appropriate to represent
slope,
and I don't know an English word either."
His answer was approximately: "In our system, the first letters of
the alphabet, a, b , c... represent the constants, the last
letters, x, y, z represent the unknown variables and the middle
letters, m, n, p... represents the parameters. When we started the
explanations of slope, it was in studying the first degree
equation: y = mx + b. x and y were the variables, b was fixed and
considered as a constant, and what was appended to the
coefficient of x as its value varied. So it was a parameter and
that is why we used m."
Andr Desch nes
__________
Date: Mon, 19 Feb 1996 12:38:34 -0500 (EST)
From: John Conway <conway@math.Princeton.EDU>
Subject: Re: GEOMETIC TERMS
But M. Risi plainly wasn't the first person to use "m" in this
connection!
It interests me that on this continent the typical form is
y = mx + b, whereas in England and in "the" Continent it is
y = mx + c. The latter form still seems to me to be more natural,
since this "c" is like the arbitrary constants in indefinite
integrals, and so it will probably be very hard to date. But
the "b" usage probably originated with the author of a particular
influential North American textbook, and maybe we can find out
just who it was.
John Conway