Toán Tính `A= 50+ 50/3+25/3+20/4+10/3+100/6.7+…+100/98.99+1/99`. 15/07/2021 By Mary Tính `A= 50+ 50/3+25/3+20/4+10/3+100/6.7+…+100/98.99+1/99`.
Đáp án: `A = 99` Giải thích các bước giải: `A = 50 + 50/3 + 25/3 + 20/4 + 20/4 + 10/3 + 100/(6.7) + ….. + 100/(98.99) + 1/99` `A = 100/(1.2) + 100/(2.3) + 1/(3.4) + 1/(4.5) + ….. + 100/(98.99) + 100/(99.100)` `A = 100 . (1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + 1/4 + …… + 1/98 – 1/99 + 1/99 – 1/100)` `A = 100 . (1 – 1/100)` `A = 100 . 99/100` `A = 9900/100` `A = 99` Trả lời
= `100/1.2` `+` `100/2.3` `+` `100/3.4` `+` `100/4.5` `+` `100/5.6` `+` `100/6.7` `+` … `+` `100/98.99` `+` `100/99.100` `=` `100` `.` `(` `1` `-` `1/2` `+` `1/2` `-` `1/3` `+` `1/3` `-` `1/4` `+` `…` `+` `1/99` `-` `1/100` ) `=` `100` `.` `(1-1/100)` `=` `100` `-` `1` `=` `99` Trả lời
Đáp án: `A = 99`
Giải thích các bước giải:
`A = 50 + 50/3 + 25/3 + 20/4 + 20/4 + 10/3 + 100/(6.7) + ….. + 100/(98.99) + 1/99`
`A = 100/(1.2) + 100/(2.3) + 1/(3.4) + 1/(4.5) + ….. + 100/(98.99) + 100/(99.100)`
`A = 100 . (1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + 1/4 + …… + 1/98 – 1/99 + 1/99 – 1/100)`
`A = 100 . (1 – 1/100)`
`A = 100 . 99/100`
`A = 9900/100`
`A = 99`
= `100/1.2` `+` `100/2.3` `+` `100/3.4` `+` `100/4.5` `+` `100/5.6` `+` `100/6.7` `+` … `+` `100/98.99` `+` `100/99.100`
`=` `100` `.` `(` `1` `-` `1/2` `+` `1/2` `-` `1/3` `+` `1/3` `-` `1/4` `+` `…` `+` `1/99` `-` `1/100` )
`=` `100` `.` `(1-1/100)`
`=` `100` `-` `1`
`=` `99`