Toán thực hiện phép tính J= 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45 08/09/2021 By Arya thực hiện phép tính J= 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45
Đáp án + Giải thích các bước giải: J =` 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45` J = `2/6 + 2/12 + 2/20 + 2/30 + 2/42 + 2/56 + 2/72 +2/90` J = `2/2.3 + 2/3.4 + 2/4.5+ 2/5.6 +2/6.7 + 2/7.8 + 2/8.9 + 2/9.10` J = `2.(1/2 – 1/3 + 1/3 – 1/4 + 1/4 – 1/5 + 1/6 – 1/7 + 1/7 – 1/8 + 1/9 – 1/10)` J = `2 . (1/2 – 1/10)` J = `2 . (5/10 – 1/10)` J = `2 . 2/5` J = `4/5` Trả lời
Đáp án: `= 4/5` Giải thích các bước giải: `J=1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45` `= 2/6 + 2/12 + 2/20 + 2/30 + 2/42 + 2/56 + 2/72 + 2/90` `= 2 . (1/6+1/12+1/20+1/30+1/42+1/28+1/72+1/90)` `= 2 . (1/(2.3)+1/(3.4)+1/(4.5)+1/(5.6)+1/(6.7)+1/(7.8)+1/(8.9)+1/(9.10))` `= 2 . ( 1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10 )` `= 2 . ( 1/2-1/10 ) = 2 . 2/5 = 4/5` Trả lời
Đáp án + Giải thích các bước giải:
J =` 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45`
J = `2/6 + 2/12 + 2/20 + 2/30 + 2/42 + 2/56 + 2/72 +2/90`
J = `2/2.3 + 2/3.4 + 2/4.5+ 2/5.6 +2/6.7 + 2/7.8 + 2/8.9 + 2/9.10`
J = `2.(1/2 – 1/3 + 1/3 – 1/4 + 1/4 – 1/5 + 1/6 – 1/7 + 1/7 – 1/8 + 1/9 – 1/10)`
J = `2 . (1/2 – 1/10)`
J = `2 . (5/10 – 1/10)`
J = `2 . 2/5`
J = `4/5`
Đáp án:
`= 4/5`
Giải thích các bước giải:
`J=1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45`
`= 2/6 + 2/12 + 2/20 + 2/30 + 2/42 + 2/56 + 2/72 + 2/90`
`= 2 . (1/6+1/12+1/20+1/30+1/42+1/28+1/72+1/90)`
`= 2 . (1/(2.3)+1/(3.4)+1/(4.5)+1/(5.6)+1/(6.7)+1/(7.8)+1/(8.9)+1/(9.10))`
`= 2 . ( 1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10 )`
`= 2 . ( 1/2-1/10 ) = 2 . 2/5 = 4/5`