小学六年级数与形，求答案。

Question

如题所述

Answer 1

2/3+2/9+2/27+2/81
=(1-1/3)+(1/3-1/9)+(1/9-1/27)+(1/27-1/81)
=1-1/3+1/3-1/9+1/9-1/27+1/27-1/81
=1-1/81
=80/81追答

2/3+2/9+2/27+2/81+2/243
=(1-1/3)+(1/3-1/9)+(1/9-1/27)+(1/27-1/81)+(1/81-1/243)
=1-1/3+1/3-1/9+1/9-1/27+1/27-1/81+1/81-1/243
=1-1/243
=242/243

3/4+3/16+3/64+3/256+3/1024
=(1-1/4)+(1/4-1/16)+(1/16-1/64)+(1/64-1/256)+(1/256-1/1024)
=1-1/4+1/4-1/16+1/16-1/64+1/64-1/256+1/256-1/1024
=1-1/1024
=1023/1024

3/4+3/16+3/64+3/256+3/1024+......
=(1-1/4)+(1/4-1/16)+(1/16-1/64)+(1/64-1/256)+(1/256-1/1024)+....
=1-1/4+1/4-1/16+1/16-1/64+1/64-1/256+1/256-1/1024+......
=1

Answer 2

都等于1