what is the infimum

No.12327382 ViewReplyOriginalReport
can you guys help me?

under normal certain stances i would say the infimum of this is -? since f(x) = x - 1/x goes to -? at x = 0
but since it says 0 < x ? 2 which makes me confused weather i can still use x = 0 -> -? for my infimum