2^(x-1)>=10^8,求x

2^(x-1)>=10^8,求x
2^(x-1)>=10^8,求x

2^(x-1)>=10^8,求x
取对数
(x-1)lg2>=lg10^8=8
lg2>0
所以x-1>=8/lg2
x>=1+8/lg2

x=1＋8log2∧10

2^(x-1)>=10^8
lg2^(x-1)>=lg10^8
(x-1)lg2>=8
x-1>=8/lg2
x>=1+8/lg2

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