已知1/1x2=1-1/2;1/2x3=1/2-1/3,1/3x4=1/3-1/4,1/4x5=1/4-1/5;…1/(n-1)n=1/n-1-1/n

问题描述:

已知1/1x2=1-1/2;1/2x3=1/2-1/3,1/3x4=1/3-1/4,1/4x5=1/4-1/5;…1/(n-1)n=1/n-1-1/n
(n为大于一的正整数).请你根据上式中包含的规律,求不等式x/2+x/6+(1/12)x+(1/20)x+…+x/(n-1)n>n-1的解集.

x/2+x/6+(1/12)x+(1/20)x+…+x/(n-1)n>n-1
x/(1x2)+x/(2x3)+x/(3x4)+x/(4x5)+……+x/[n(n-1)]>n-1
x[1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+……+1/(n-1)-1/n]>n-1
x(1-1/n)>n-1
x(n-1)/n>n-1
∵n>1
∴n-1>0
x>n