Tìm x biết 1+1/3+1/6+1/10+...+2/x(x+1)=1/1991/1993
Bài 4:Tìm x biết:
a,15.8+1/8.11+1/11.14+...+1/x.(x+3)=101/1540
b,1+1/3+1/6+1/10+...+1/x.(x+1)+2=1 và 1991/1993
1+ 1/3+1/6+1/10+...+1/x.(x+1):2= 1 1991/1993
1 1991/1993 la hon so
Tìm x,biết rằng:
a)1/5.8+1/8.11+1/11.14+...1/x(x+3)=101/1540
b)1+1/3+1/6+1/10+...+1/x(x+1):2=1 1991/1993
*1 1991/1993 là hỗn số nha
1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{10}\) +...+ \(\dfrac{1}{x\left(x+1\right):2}\) = \(1\dfrac{1991}{1993}\)
1+1/3+1/6+1/10+.....+1/x(x+1)=1991/1993
1+1/3+1/6+1/10+.....+1/x(x+1)=1991/1993
1+1/3+1/6+11/10+.......+1/x(x+1):2=1va 1991/1993
Tính nhanh
1/3 + 1/6 + 1/10 +....+ 1/x(x + 1) = 1 + 1991/1993