Phi

Date: 05/18/97 at 22:12:09
From: Roz
Subject: phi

What is phi? I heard it's kind of like pi.

Date: 05/18/97 at 22:54:13
From: Doctor Mike
Subject: Re: phi

Hello Roz,
  
Phi is one of the 24 letters in the Greek alphabet.  Sometimes it
is pronounced like the first part of the English word "fine," and
sometimes like the English word "fee."  Use of the Greek alphabet is 
popular in writings about math, probably since some of the early great 
mathematicians, like Euclid and Pythagoras, were Greeks who lived 
between two and three thousand years ago.  
  
Greek letters are used as names for college fraternities and 
sororities.  They are also used as names of some professional
organizations, like Kappa Sigma for the legal profession.  Also, an 
organization for college students who get excellent grades is called 
Phi Beta Kappa.  
   
The Greek letter pi is often used to represent the ratio of the 
circumference of any circle to its diameter:

  Pi = 3.14159
  http://mathforum.org/dr.math/faq/faq.pi.html

while the Greek letter phi is often used to represent another famous
ratio:

  Golden Ratio, Fibonacci Sequence
  http://mathforum.org/dr.math/faq/faq.golden.ratio.html

I hope this helps. 

-Doctor Mike,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/