计算:(1+2^-1⼀8)(1+2^-1⼀4)(1+2^-1⼀2)

要有步骤或解析
2025-01-07 15:27:52
推荐回答(2个)
回答1:

解:原式=[1-2^(-1/8)][1+2^(-1/8)][1+2^(-1/4)][1+2^(-1/2)]/[1-2^(-1/8)]
=[1-2^(-1/4)][1+2^(-1/4)][1+2^(-1/2)]/[1-2^(-1/8)]
=[1-2^(-1/2)][1+2^(-1/2)]/[1-2^(-1/8)]
=(1-1/2)/[1-2^(-1/8)]
=(1/2)/[1-2^(-1/8)]
=1/[2-2^(7/8)]

回答2:

这个式子乘以(1-2^-1/8)等于
(1+2^-1/8)(1+2^-1/4)(1+2^-1/2)(1-2^-1/8)
=(1-2^-1/4)(1+2^-1/4)(1+2^-1/2)
=(1-2^-1/2)(1+2^-1/2)
=1-2^-1
=1/2
所以原式=1/[2(1-2^-1/8)]