n = 3, 1(n−1)!−1(n+1)!=1(3−1)!−1(3+1)!\;\frac{1}{(n-1)!} - \frac{1}{(n+1)!} = \frac{1}{(3-1)!} - \frac{1}{(3+1)!}(n−1)!1−(n+1)!1=(3−1)!1−(3+1)!1
= 12−124=12−124\;\frac{1}{2} - \frac{1}{24} = \frac{12-1}{24}21−241=2412−1
= 1124\;\frac{11}{24}2411
