Trang chủ » Hỏi đáp » Môn Toán 1/3 + 1/ 6 + 1/10 + … + 2/x.(x+1) = 998/1000 01/07/2023 1/3 + 1/ 6 + 1/10 + … + 2/x.(x+1) = 998/1000
1/3+1/6+1/10+…+2/x(x+1)=998/1000 2/6+2/12+2/20+…+2/x(x+1)=998/1000 2[1/2.3+1/3.4+1/4.5+…+1/x(x+1)]=998/1000 2[1/2-1/3+1/3-1/4+1/4-1/5+…+1/x+1/(x+1)]=998/1000 2.[1/2-1/(x+1)]=998/1000 1/2-1/(x+1)=499/1000 1/(x+1)=1/2-499/1000 1/(x+1)=1/1000 => x=999 Trả lời
2 bình luận về “1/3 + 1/ 6 + 1/10 + … + 2/x.(x+1) = 998/1000”