Science:Math Exam Resources/Courses/MATH220/December 2010/Question 01 (a)/Solution 1

By definition, we have

$\displaystyle f^{-1}(D)=\{x\in A:f(x)\in D\}$

and

$\displaystyle f(C)=\{y\in B:\exists x\in C{\text{ such that }}f(x)=y\}$