In fact, this is a characteristic
difference between a finite and an infinite set EXERCISE 1 2
1 Show that the function f : R∗∗∗∗∗ → R∗∗∗∗∗ defined by f (x) = 1
x  is one-one and onto,
where R∗∗∗∗∗ is the set of all non-zero real numbers