我们已经知道,a~2=a×a、a~3=a×a×a、a~4=a×a×a×a……,那么,加以扩大,就有a~n=a×a×a×a×……×a共n个式中表明,n个相同因子a的乘积可以写成a~n。数学上将n个相同因子的乘积叫做n次幂,其中a叫做幂的底数,n叫做幂的指数,a~n也就是a的n次幂,或叫做a的n次乘方。在上述定义中,n是正整数,所以叫做“正整数指数幂”。那么,如果n是零、负数、小数或分数, We already know that a~2=a×a,a~3=a×a×a,a~4=a×a×a×a..., then, to be enlarged, there is a~n=a×a ×a×a×... ×a A total of n formulas indicate that the product of n identical factors a can be written as a~n. Mathematically, the product of n identical factors is called the n-th power, where a is called the power base, n is called power exponent, a~n is also a power of n, or called a power n times. In the above definition, n is a positive integer, so it is called a “positive integer exponent power”. Then if n is zero, negative, decimal, or fraction,