(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15 =【(2+1)/2】【(2^2+1)/2^2】【(2^4+1)/2^4】【(2^8+1)/2^8】+1/2^15 =【(2+1)(2^2+1)(2^4+1)(2^8+1) 】/2^15+1/2^15 =【(2+1)(2^2+1)(2^4+1)(2^8+1) +1】/2^15 =【(2-1)(2+1)(2^2+1)(2^4+1)(2^8+1) +1(2-1)】/【2^15×(2-1)】 =【(2^2-1)(2^2+1)(2^4+1)(2^8+1) +1】/2^15 =【(2^4-1)(2^4+1)(2^8+1) +1】/2^15 =【(2^8-1)(2^8+1) +1】/2^15 =(2^16-1+1)/2^15 =2^16/2^15 =2