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
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