а) (4/21) (7/15) (15/16n) = (4715) / (211516n) = 420 / (315 * 16n) = 420 / 5040n = 1 / 12n
б) (1 + 4/9) (1 + 9/13) (1 + 7/11) = (13/9) (22/13) (18/11) = (13 22 18) / (9 13 11) = 4296 / 1287 = 4 / 3
а) (4/21) (7/15) (15/16n) = (4715) / (211516n) = 420 / (315 * 16n) = 420 / 5040n = 1 / 12n
б) (1 + 4/9) (1 + 9/13) (1 + 7/11) = (13/9) (22/13) (18/11) = (13 22 18) / (9 13 11) = 4296 / 1287 = 4 / 3