Question

1+1/3+1/6+1/10+...+1/1(x+1):2 = 1+1991/1993

chi tiết nha

Answer 1

Hình như sai đề, mk sửa đề nha

1+1/3+1/6+1/10+...+1/x(x+1):2=1+1991/1993

Làm:

2/6+2/12+2/20+2/x(x+1)=1991/1993

2/2.3+2/3.4+2/4.5+...+2/x(x+1)=1991/1993

2(1/2.3+1.3.4+1/4.5+...+1/x(x+1)=1991/1993

2(1/2-1/3+1/3-1/4+1/4-1/5+...+1/x-1/x+1)=1991/1993

2(1/2-1/x+1)=1991/1993

1/2 - 1/x+1=1991/3986

1/x+1=1/1993

Suy ra x+1=1993

x=1992

Answer 2

Bài này đơn giản, t..i..c..k rùi mk làm cho, ko lừa đâu

Answer 3

1+1/3+1/6+1/10+...+1/1(x+1):2 = 1+1991/1993

1/2.(1+1/3+1/6+1/10+...+1/x(x+1)=3984/3986

1/2+1/6 +1/12+....+1/x(x+1)=3984/3986

1/1.2+1/2.3+1/3.4+...+1/x(x+1)=3984/3986

2-1/1.2+3-2/2.3+4-3/3.4+...+x+1-x/x.(x+1)

1-1/2+1/2-1/3+1/3-1/4+...+1/x-1x+1=3984/3986

1-1/x+1=3984/3986

1/x+1=1-3984/3986

1/x+1=2/3986=1/1993

x+1=1993

x=1993-1

x=1992

 

 

Answer 4

1+1/3+1/6+1/10+...+1/1(x+1):2 = 1+1991/1993

1/2.(1+1/3+1/6+1/10+...+1/x(x+1)=3984/3986

1/2+1/6 +1/12+....+1/x(x+1)=3984/3986

1/1.2+1/2.3+1/3.4+...+1/x(x+1)=3984/3986

2-1/1.2+3-2/2.3+4-3/3.4+...+x+1-x/x.(x+1)

1-1/2+1/2-1/3+1/3-1/4+...+1/x-1x+1=3984/3986

1-1/x+1=3984/3986

1/x+1=1-3984/3986

1/x+1=2/3986=1/1993

x+1=1993

x=1993-1

x=1992

Answer 5

nguyễn tuấn minh tui chưa hiểu lắm sao hỗn số lại giữ nguyên z

Answer 6

sai đề rùi

Answer 7

1+1991/1993=3984/1993 mới đúng chứ!!!

Answer 8

Đề của tớ giống bạn nhưng kết quả khác cơ:

   \(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{x\left(x+1\right):2}=1\frac{19991}{1993}\)

Answer 9

của-tui-khác-chút-xíu-là-vế-phải-ko-có-p/số1991/1993

Answer 10

mình không tim cái này!