Đáp án+Giải thích các bước giải:
`A=(1/2+1/12+1/30+...+1/9120+1/9506+1/9900)/(50-50/51-51/52-52/53-...-97/98-98/99-99/100)`
`A=[1/1.2+1/3.4+1/5.6+...+1/95.96+1/97.98+1/99.100]/[(1-50/51)+(1-51/52)+(1-52/53)+...+(1-97/98)+(1-98/99)+(1-99/100)`
`A=[1-1/2+1/3-1/4+1/5-1/6+...+1/95-1/96+1/97-1/98+1/99-1/100]/[1/51+1/52+1/53+....+1/98+1/99+1/100]`
`A=[(1+1/3+1/5+....+1/95+1/97+1/99)-(1/2+1/4+1/6+....+1/96+1/98+1/100)]/[1/51+1/52+1/53+.....+1/98+1/99+1/100`
`A=[(1+1/3+1/5+...+1/95+1/97+1/99)+(1/2+1/4+1/6+...+1/96+1/98+1/100)-2.(1/2+1/4+1/6+....+1/96+1/98+1/100)]/[1851+1/52+1/53+...+1/98+1/99+1/100]`
`A=[(1+1/2+1/3+1/4+...+1/98+1/99+1/100)-(1+1/2+1/3+...+1/48+1/49+1/50)]/[1/51+1/52+1/53+...+1/98+1/99+1/100]`
`A=[1/51+1/52+1/53+....+1/98+1/99+1/100]/[1/51+1/52+1/53+...+1/98+1/99+1/100]`
`A=1`
Vậy `A=1`
`______________________`
Chúc bạn học tốt!!!
`Rùa~ ~ ~`
