Đáp án:
`A>B`
Giải thích các bước giải:
`A=2/3+14/15+34/35+62/63+98/99+142/143+194/195`
`=>A=(1-1/3)+(1-1/15)+(1-1/35)+(1-1/63)+(1-1/99)+(1-1/143)+(1/195)`
`=>A=7-(1/3+1/15+1/35+1/63+1/99+1/143+1/195`
`=>A=7-(1/1.3+1/3.5+1/5.7+1/7.9+1/9.11+1/11.13+1/13.15)`
`=>A=7-1/2(2/1.3+2/3.5+2/5.7+2/7.9+2/9.11+2/11.13+2/13.15)`
`=>A=7-1/2(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13+1/13-1/15)`
`=>A=7-1/2(1-1/15)`
`=>A=7-1/2*14/15`
`=>A=7-7/15>6` (Vì `7/15∉N text(*)`)
`B=5-1/2^2+1/3^3+1/4^4+1/5^5+1/6^6+1/7^7`
`=>B=5-(1/2^2-1/3^3-1/4^4-1/5^5-1/6^6-1/7^7)`
`=>B<5`
`=>A>6>5>B`
Vậy `A>B`.
