There are thousands of formulas to calculate Pi. Here is one that has been used for about 300 years:
Pi/4 =4 arctan(1/5) - arctan(1/239). Here is another pretty one found by Euler:
(Pi^2)/6 = 1/1^2 + 1/2^2 + 1/3^2 + 1/4^2 + 1/5^2...........to infinity.
What is the full equation of pi?
