简便运算: (9-10)*(10-11)*(11-12)*…*(108-109);
问题描述:
简便运算: (9-10)*(10-11)*(11-12)*…*(108-109);
答
(9-10)*(10-11)*(11-12)*…*(108-109)
=-1*(-1)*(-1)*(-1)*....(-1)
=1
答
解:
(9-10)*(10-11)*(11-12)*…*(108-109);
=(-1)(-1)(-1)(-1)...(-1)
=(-1)^(108-9+1)
=(-1)^100
=1