piPEN(PE)

fx with in = error [%] & out = iterations for pi series approx: (pi^2)/6 = sum (1/k^2) at k = 1 to N

%% Function that computes
% Output: N = the number of iterations (if >= 1e5, then N = Inf), given
% Input: PE = percent error [%]
% to approximate pi using the pi series:
% (pi^2)/6 = summation of (1/k^2) from k = 1 to N
%
% Author: Roche de Guzman, Ph.D.
% Hofstra University
function N = piPEN(PE)