`Answer:`
`1/3+1/6+1/10+...+2/(x.(x+1))=2008/2010`
`=2/6+2/12+2/20+...+2/(x.(x+1))=2008/2010`
`=2/(2.3)+2/(3.4)+2/(4.5)+...+(2)/(x.(x+1))=2008/2010`
`=2.(1/2-1/3+1/3-1/4+...+1/x(x+1))=2008/2010`
`=1/2-1/3+1/3-1/4+...+1/x-1/(x+1)=1004/2010`
`=1/2-1/(x+1)=1004/2010`
`=>1/(x+1)=1/2-1004/2010`
`=>1/(x+1)=1/2010`
`=>x+1=2010`
`=>x=2010-1`
`=>x=2009`
tìm STN x biết:1/3+1/6+1/10+...+2/x.(x+1)=2008/2010
Tìm x biết 1/1 +1/3 + 1/6 + ... + 2/x.(x+1) = 1\(\frac{2008}{2010}\)
Tìm x biết 1/1+1/3+1/6+...+2/x(x+1)= \(1\frac{2008}{2010}\)
Tìm x biết 1/1 + 1/3 + 1/6 + . . . + 2/x(x+1) = \(1\frac{2008}{2010}\)
Tìm x, biết:
\(\left(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2008}\right).x=\frac{2009}{1}+\frac{2010}{2}+\frac{2011}{3}+...+\frac{4016}{2008}-2008\)
1+\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+....+\frac{2}{x.\left(x+1\right)}=1\frac{2008}{2010}\)
tìm x biết 2/2*3+2/3*4+2/4*5+...+2/x*(x+1)+2008?2010
Tìm x biết 1/3+1/6+1/10+2/x.(x+1)=2010/1006
Tìm các số nguyên x, y mà (x-1).(3-y) = 2
Tìm STN x, biết 1/3 +1/6+1/10+...+2/ x.(x+1)
Chứng minh rằng 1+1/2+1/3+...+1/21999>1000
