p=[log5(6)]×[log6(7)]×[log7(8)]×[log8(9)]×[log9(10)]
=(lg6/lg5)×(lg7/lg6)×(lg8/lg7)×(lg9/lg8)×(lg10/lg9)
=lg10/lg5
=log(5×2)/lg5
=(lg5+lg2)/lg5
=1 +log5(2)