计算下列各式,并说明理由 . (1) (62)4 ; (2) (a2)3 ; (3) (am)2 ; (4) (am)n .
解:(1) (62)4
(2) (a2)3
(3) (am)2
= 62·62· 62·62
=62+2+2+2
=68
= a2·a2·a2
=a2+2+2
=a6
=am·am
=am+m
(4) (am)n
=am·am· … ·am
=amn
(幂的意义)
(同底数幂的乘法性质)
(乘法的意义)
=am+m+ … +m