Date: 10/26/2000 at 09:55:40 From: Daniel Geraldes Uzueli Subject: The Pi Symbol - Other Math Uses Dear Sir, I would like to confirm with you whether "Pi" also means, in one equation, the following: Pi(Xi) [i = 1 to f] = the multiplication of the terms of X with i changing from 1 until f. Is it correct? Thank you for your attention, Daniel Uzueli
Date: 10/26/2000 at 10:35:49 From: Doctor TWE Subject: Re: The Pi Symbol - Other Math Uses Hi Daniel - thanks for writing to Dr. Math. You are correct, this: would be read as "the product of all x-sub-i's for i is equal to 1 through f," and means to multiply all of the x terms beginning with the first and ending with the fth. Pi is a letter in the Greek alphabet that is their equivalent of our letter P. In math and science, we frequently use Greek letters to represent variables, constants, functions, and the like. Note that when we use pi to represent the ratio of the circumference to the diameter of a circle (3.14159...) we use the lowercase letter pi; it usually has a curvy top and short legs: To represent the product function, we use the uppercase pi, which generally has a straight top and longer legs: The product pi notation was developed to correspond to the summation sigma notation (which uses an uppercase Greek letter sigma in a similar fashion: I hope this helps. If you have any more questions, write back. - Doctor TWE, The Math Forum http://mathforum.org/dr.math/
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