Mathematical Notation

Date: 11/1/95 at 17:45:51
From: Beau Leonhart
Subject: mathematical alphabet

A student asked me why k was chosen, rather than c, for the 
constant of variation in y = kx or xy = k in direct and inverse 
variation questions.

I don't really know the history or how we inherited the use of k.

Is there a source that explores the "mathematical alphabet"?

I know the letters in the beginning of the alphabet are often used 
as parameters in forms such as Ax + By = C or ax^3 + bx^2 + cx + d 
= 0.  The letters at the end of the alphabet are often variables.  
e is approximately 2.18. f,g, and h are used for functions such 
as, f(x), g(x), or h(x).  i is the imaginary number.  j and k are 
used for vectors. l is often used to name a line in geometry.  m 
is slope (why?). n is a variable of integer.  What is o? p? q, r 
s, and t are also used for variables like x, y and z, or 
functions. r is also used in polar coordinates (r, theta) or is it 
(theta, r)?  u and v are also vectors.

Anyway, I would appreciate the answer to my student's question 
about k and or a source of more information on the use of the 
letters in mathematical notation.

 Thanks.
Beau Leonhart

Date: 11/12/95 at 14:30:57
From: Doctor Ken
Subject: Re: mathematical alphabet

Hello!

I'm afraid I don't know the answer to the question about k, but I 
can give you a reference that may be very interesting to you.  
It's a book called "The History of Mathematical Notation" by 
Florian Cajori.  It's a 2-volume set that is fairly detailed.  
Hope you find it useful!

-Doctor Ken,  The Geometry Forum