Toán Tính nhanh , N = 1/1×5 + 1/5×10 + 1/10×15 + 1/15×20 + ……….. + 1/2005×2010 16/09/2021 By Caroline Tính nhanh , N = 1/1×5 + 1/5×10 + 1/10×15 + 1/15×20 + ……….. + 1/2005×2010
`N=1/(1×5)+1/(5×10)+…+1/(2005×2010)` `N=1/(1×5)+1/5(5/(5×10)+5/(10×15)+…+5/(2005×2010)` `N=1/5+1/5(1/5-1/10+1/0-1/15+…+1/2005-1/2010)` `N=1/5+1/5(1/5-1/2010)` `N=1/5(1+1/5-1/2010)` `N=1/5 . 2411/2010` `N=2411/10050` Trả lời
`N=1/(1×5)+1/(5×10)+…+1/(2005×2010)`
`N=1/(1×5)+1/5(5/(5×10)+5/(10×15)+…+5/(2005×2010)`
`N=1/5+1/5(1/5-1/10+1/0-1/15+…+1/2005-1/2010)`
`N=1/5+1/5(1/5-1/2010)`
`N=1/5(1+1/5-1/2010)`
`N=1/5 . 2411/2010`
`N=2411/10050`
Đáp án:
Giải thích các bước giải: