A=1/3.5+1/5.7+1/7.9….+1/97.99 Chú thick: . có nghĩa là dấu nhân 19/09/2021 Bởi Alice A=1/3.5+1/5.7+1/7.9….+1/97.99 Chú thick: . có nghĩa là dấu nhân
Đáp án: Giải thích các bước giải: $A=\dfrac{1}{3.5}+\dfrac{1}{5.7}+…+\dfrac{1}{97.99}$ $ $ `=\frac{1}{2}.(\frac{2}{3.5}+\frac{2}{5.7}+…+\frac{2}{97.99})` ` ` `=\frac{1}{2}.(\frac{1}{3}-\frac{1}{99})` ` ` `=\frac{1}{2}.\frac{32}{99}` ` ` `=\frac{16}{99}` Bình luận
`Đáp` `án:` `A=` `1/3.5` + `1/5.7` + `1/7.9` `+… +` `1/97.99` `=` `1/2` `.` `(2/3.5` `+` `2/5.7` `+` `2/7.9` `+…+` `2/97.99)` `=` `1/2` `.` `(` `1/3` `-` `1/5` `+` `1/5` `-` `1/7` `+` `1/7` `-` `1/9` `+…+` `1/97` `-` `1/99` `)` `=` `1/2` `.` `(` `1/3` `+` `0` `+` `0` `+…+` `0` `-` `1/99` `)` `=` `1/2` `.` `(1/3` `-` `1/99` `)` `=` `1/2` `.` `32/99` `=` `16/99` Bình luận
Đáp án:
Giải thích các bước giải:
$A=\dfrac{1}{3.5}+\dfrac{1}{5.7}+…+\dfrac{1}{97.99}$
$ $
`=\frac{1}{2}.(\frac{2}{3.5}+\frac{2}{5.7}+…+\frac{2}{97.99})`
` `
`=\frac{1}{2}.(\frac{1}{3}-\frac{1}{99})`
` `
`=\frac{1}{2}.\frac{32}{99}`
` `
`=\frac{16}{99}`
`Đáp` `án:`
`A=` `1/3.5` + `1/5.7` + `1/7.9` `+… +` `1/97.99`
`=` `1/2` `.` `(2/3.5` `+` `2/5.7` `+` `2/7.9` `+…+` `2/97.99)`
`=` `1/2` `.` `(` `1/3` `-` `1/5` `+` `1/5` `-` `1/7` `+` `1/7` `-` `1/9` `+…+` `1/97` `-` `1/99` `)`
`=` `1/2` `.` `(` `1/3` `+` `0` `+` `0` `+…+` `0` `-` `1/99` `)`
`=` `1/2` `.` `(1/3` `-` `1/99` `)`
`=` `1/2` `.` `32/99`
`=` `16/99`