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 Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...The Space and Astronomy Agora Three Slices Of Pi Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response ToPosted by Kyle on September 4, 2002 20:19:46 UTC

Loosely related to Luis, Paul and Dr. Dick's topic of mathematical "tricks", here are some interesting real number infinite expansions that can be used to express pi:

(where the value of pi= 3.14159265358979323846...)

pi expression #1:
pi = square root of {6 (1/1 + 1/4 + 1/9 + 1/25 + 1/36 + 1/49 + ...)}

pi expression #2:
pi = 2 {(2/1)(2/3)(4/3)(4/5)(6/5 )(6/7)(8/7)(8/9)...}

pi expression #3:
pi = 4 (1/1 - 1/3 + 1/5 -1/7 + 1/9 - 1/11 + ...)

Note: If you’re trying to verify these three separate expressions by calculator, just realize that in order for the calculation to come out exactly to the value pi, the infinite expansion has to be completed (for every-day life we almost always approximate infinite expansions, but for mathematical statements like these three expressions to work, the real numbers have to be specified exactly).

-Kyle