(1+1/2)(1+1/4)(1+1/16)+...(1+1/2^2n)的值

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(1+1/2)(1+1/4)(1+1/16)+...(1+1/2^2n)的值

(1+1/2)(1+1/4)(1+1/16)+...(1+1/2^2n) =2(1/2)(1+1/2)(1+1/4)(1+1/16)+……(1+1/2^2n) =2(1-1/2)(1+1/2)(1+1/4)(1+1/16)+……(1+1/2^2n) =2(1-1/4)(1+1/4)(1+1/16)+……(1+1/2^2n) =2(1-1/16)(1+1/16)……(1+1/2^2n) =…… =2(1-1/2^2n)(1+1/2^2n) =2(1-1/2^4n) =(2^4n-1)/2^(4n-1) (上式的分子是 2的4n次方-1 ,而分母是2的4n-1次方)