4. Consider the following functions, where I and J denote two subsets of the set R of real numbers. f: R R x 1/x f(): IJ x f(x) (a) What is the domain of definition of f? (b) Let y be an element of the codomain of f. Solve the equation f(x)=y in x. Note that you may have to consider different cases, depending on y. (c) What is the range of f? (d) Is f total, surjective, injective, bijective? (e) Find a pair (I,J) such that f() is bijective and its range is the range of f. What is then the inverse of f(L,J)?