Letters for Variables
Date: 11/19/2001 at 10:18:55 From: Spencer Moore Subject: Variables Why do we use letters for variables?
Date: 11/19/2001 at 10:51:38 From: Doctor Ian Subject: Re: Variables Hi Spencer, It's much quicker to write a = lw than area(rectangle) = length * width It's the same reason we use operators instead of words like: The area of a rectangle is equal to the product of the length of the rectangle and the width of the rectangle. A lot of math involves writing the same equations over and over, with small changes. For example: a = lw = (h - 5)(h + 2) = h^2 - 5h + 2h - 10 = h^2 - 3h - 10 The more you do this, the more you appreciate being able to write what you want to say with as few symbols as possible. In language, we do a similar thing by using pronouns. That is, it's easier to write (and say) Fred and Janet got into their car and drove to their house, where their dog was waiting to greet them. than Fred and Janet got into the car belonging to Fred and Janet and drove to the house belonging to Fred and Janet, where the dog belonging to Fred and Janet was waiting to greet Fred and Janet. It's also a lot easier to read! The use of letters to represent general numbers goes all the way back to Greek antiquity. For information about the beginning uses of letters for variables, see Jeff Miller's Web page, Earliest Uses of Symbols for Variables: http://jeff560.tripod.com/variables.html - Doctors Ian and Sarah, The Math Forum http://mathforum.org/dr.math/
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