Drill Definition and 51 Threads

Maybe I'm a little slow, but the true meaning of pi just occurred to me. tan(pi/4) = 1 arctan(x) = [sum]n=0[oo] (-1)n * [ x2n+1 / (2n + 1) ] pi = 4 * arctan(1) = 4 * [sum]n=0[oo] (-1)n * [ 1 / (2n + 1) ] = 4 * ( 1 - 1/3 + 1/5 - 1/7 + 1/9 - 1/11 + ... ) = 4 * ( 2/3 + 2/35 + 2/99 + ...