1/2+1/4+1/8+1/16+1/32+...+1/256简便运算

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1/2+1/4+1/8+1/16+1/32+...+1/256简便运算

1/2+1/4+1/8+1/16+1/32+...+1/256简便运算
1/2+1/4+1/8+1/16+1/32+...+1/256简便运算

1/2+1/4+1/8+1/16+1/32+...+1/256简便运算
1/2+1/4+1/8+1/16+1/32+...+1/256
=1-1/256
=255/256

1/2+1/4+1/8+1/16+1/32+...+1/256
=1/2+1/4+1/8+1/16+1/32+...+(1/256+1/256)-1/256
=1/2+1/4+1/8+1/16+1/32+...+(1/128+1/128)-1/256
=1/2+1/2-1/256
=1-1/256
=255/256

过程如下
1/2+1/4+1/8+1/16+1/32+...+1/256
=1/2+(1/2-1/4)+(1/4-1/8)+(1/8-1/16)+(1/16-1/32)+····(1/128-1/256)
=1/2+1/2-1/256(中间的正负抵消)
=1-1/256
=255/256