设n为正整数,解不等式|5n\(n+1)-5|答案是n＞4999

设n为正整数,解不等式|5n\(n+1)-5|答案是n＞4999
设n为正整数,解不等式|5n\(n+1)-5|
答案是n＞4999

设n为正整数,解不等式|5n\(n+1)-5|答案是n＞4999
|5n\(n+1)-5|

|5n/(n+1)-5|<0.001
5n/(n+1)-5<0.001或者-(5n/(n+1)-5)<0.001
5n/(n+1)-5=5n/(n+1)-5(n+1)/(n+1)=(5n-5n-5)/(n+1)=-5/(n+1)
5n/(n+1)-5<0.001
-5/(n+1)<0.001
(n+1)>-5000
n>-4999
-(5n/(n+1)-5)<0.001
5/(n+1)<0.001
(n+1)>5000
n>4999

n为正整数>4999

n为正整数
所以5n/(n+1)-5=-5/(n+1) <0
所以|5n\(n+1)-5|=5/(n+1)<0.001
n+1>5000
n>4999