Tính tổng sau: P=10/56+10/140+10/260+…..+10/1400 05/10/2021 Bởi Rose Tính tổng sau: P=10/56+10/140+10/260+…..+10/1400
`10/56+10/140+10/260+…..+10/1400` `= 5/28+5/70+5/130+…+5/700` `= 5(1/(4.7)+1/(7.10)+1/(10.13)+…+1/(25.28))` `= 5(3/(4.7)+3/(7.10)+3/(10.13)+…+3/(25.28))` `= 5/3.(1/4-1/7+1/7-1/10+1/10-1/13+…+1/25-1/28)` `= 5/3.(1/4-1/28)` `= 5/3.3/14` `= 5/14` Bình luận
Đáp án: Giải thích các bước giải: P=10/56+10/140+10/260+…..+10/1400 = 5/28+ 5/70+..+ 5/700 = 5/4.7+ 5/7.10+ ..+ 5/25.28 = 5.( 1/4.7+ 1/7.10+ 1/10.13+…+ 1/25/28) = 5/3.( 3/4.7+ 3/7.10+..+ 3/25.28) = 5/3.( 1/4- 1/7+ 1/7- 1/10+…+ 1/25- 1/28) = 5/3.( 1/4- 1/28) = 5/3. 6/28 = 5/3. 3/14 = 5/14 Vậy P= 5/14 Chúc bạn học tốt! Bình luận
`10/56+10/140+10/260+…..+10/1400`
`= 5/28+5/70+5/130+…+5/700`
`= 5(1/(4.7)+1/(7.10)+1/(10.13)+…+1/(25.28))`
`= 5(3/(4.7)+3/(7.10)+3/(10.13)+…+3/(25.28))`
`= 5/3.(1/4-1/7+1/7-1/10+1/10-1/13+…+1/25-1/28)`
`= 5/3.(1/4-1/28)`
`= 5/3.3/14`
`= 5/14`
Đáp án:
Giải thích các bước giải:
P=10/56+10/140+10/260+…..+10/1400
= 5/28+ 5/70+..+ 5/700
= 5/4.7+ 5/7.10+ ..+ 5/25.28
= 5.( 1/4.7+ 1/7.10+ 1/10.13+…+ 1/25/28)
= 5/3.( 3/4.7+ 3/7.10+..+ 3/25.28)
= 5/3.( 1/4- 1/7+ 1/7- 1/10+…+ 1/25- 1/28)
= 5/3.( 1/4- 1/28)
= 5/3. 6/28
= 5/3. 3/14
= 5/14
Vậy P= 5/14
Chúc bạn học tốt!