(1+1/2)(1+1/2的平方)(1+1/2的四次方)(1+1/2的八次方)(1+1/2的十六次方)+(1+2的31次方)

问题描述:

(1+1/2)(1+1/2的平方)(1+1/2的四次方)(1+1/2的八次方)(1+1/2的十六次方)+(1+2的31次方)

原式=2(1-1/2)(1+1/2)(1+1/2^2)(1+1/2^4)……(1+1/2^16)+(1+1/2^31)
=2(1-1/2^32)+(1+1/2^31)=2-1/2^31+1+1/2^31
=3

(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)(1+1/2^16)+(1+2^31)=(1-1/2)(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)(1+1/2^16)/(1-1/2)+ 1+1/2^31
=(1-1/2²)(1+1/2^2)(1+1/2^4)(1+1/2^8)(1+1/2^16)/(1-1/2)+ 1+1/2^31
=(1-1/2^4)(1+1/2^4)(1+1/2^8)(1+1/2^16)/(1-1/2)+ 1+1/2^31
=(1-1/2^8)(1+1/2^8)(1+1/2^16)/(1-1/2)+ 1+1/2^31
=(1-1/2^16)(1+1/2^16)×2+ 1+1/2^31
=2-1/2^31+1+1/2^31
=3