Which of the following function(s) from f: A → A are invertible, where x ∈ [−1, 1] ?
Answer & explanation
Correct answer: option 2
Clearly (c) and (d) are ruled out as these are many-one. Also $f(x)=\frac{x}{2}$ is one-one but not
onto. $g(x)=\sin(\frac{πx}{2})$ is both one-one and onto.