Tìm x biết :1/2+1/6+1/12+1/20+1/30+1/x=41/42
A=1/2+1/6+1/12+1/20+1/30......1/9900
A=1/2+1/6+1/12+1/20+1/30+1/42
Tính giá trị biểu thức:
A= 1/2+1/6+1/12+1/20+1/30....+1/9900
Tính T biết : 1/2+1/6+1/12+1/20+1/30+.........+1/9702+1/9900
1/2+1/6+1/12+1/20+1/30+1/x=41/42
tìm x
tính giá trị biểu thức
a = 1 /2 + 1/6 + 1 /12 + 1/20 + 1/30 ....+ 1/9900
a,1/2+1/6+1/12+1/20+1/30+1/x=41/42