1、(1+1/2)(1+2的平方分之一)(1+2的四次方分之一)(1+2的八次方分之一)+2的十五次方分之一
(1+1/2)(1+2/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
=2(1-1/2)(1+1/2)(1+2/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
=2(1-1/2^2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
=2(1-1/2^4)(1+1/2^4)(1+1/2^8)+1/2^15
=2(1-1/2^8)(1+1/2^8)+1/2^15
=2(1-1/2^16)+1/2^15
=2-1/2^15+1/2^15
=2
2、已知2的96次方-1可以被在60至70之间的两个整数整除,则这两个整数是多少?
63,65
理由:
2^96-1
=(2^48+1)(2^48-1)
=(2^48+1)(2^24+1)(2^24-1)
=(2^48+1)(2^24+1)(2^12+1)(2^12-1)
=(2^48+1)(2^24+1)(2^12+1)(2^6+1)(2^6-1)
=(2^48+1)(2^24+1)(2^12+1)(64+1)(64-1)
=(2^48+1)(2^24+1)(2^12+1)*65*63
3、已知3的n次方+m能被13整除,求证3的(n+3)次方+m也能被13整除
证明:3^(n+3)+m=3^n×(3^3)+m=27×3^n+m=26×3^n+3^n+m
26×3^n能被13整除,3^n+m能被13整除,所以相加能被13整除.