Similarly,
| x-2 |+| x-2017 |≥| 2017-2 | = 2015 is an equal sign if and only if 2≤x≤20 17.
…………
| x-1008 || x-1009 |≥|101008 | = 2 if and only if1008 ≤ x ≤/.
|x- 1009|≥0, if and only if x= 1009, take the equal sign.
If and only if x= 1009, | x-1| x-2018 |, | x-2 ||| x-2017 |, ..., | x-/kloc-0.
|x- 1|+|x-2|+|x-3|+...+|x-20 18|≥0+2+...+20 17
=2( 1+2+...+ 1008)
= 10 17072