MATHEMATICS · Single correct · AoPS · Mathematics · Special Functions · Special Functions
Problem
Let f:(2,4)→(1,3) be a function defined by f(x)=x−[2x], where [⋅] denotes the greatest integer function. Then f−1(x) is equal to:
(a) 2x
(b) x+[2x]
(c) x+1
(d) x−1