问题
解答题
探索题:
(x-1)(x+1)=x2-1;
(x-1)(x2+x+1)=x3-1;
(x-1)(x3+x2+x+1)=x4-1;
(x-1)(x4+x3+x2+x+1)=x5-1
…
(1)试求:26+25+24+23+22+2+1的值;
(2)判断22014+22013+22012+22011+…+22+2+1的值的个位上是几?
答案
(1)原式=(2-1)(26+25+24+23+22+2+1)
=27-1
=127;
(2)原式=(2-1)(22014+22013+22012+22011+…+22+2+1)
=22015-1,
则结果个位上数字为7.