(a)

The functions are and .

The domain and range of the both  and  consist of all real numbers, can conclude that both composite functions eixst for all .

To verify that and are inverse functions, find  and .

Find .

.

Find .

.

Since, the functions  and are inverse functions.

(b).

Graph the functions and on the same window.

(1). Draw the coordinate plane.

(2). Graph the functions.

Graph :

Observe the graph:

The functions and are symmetrical about the line . 

So, graphically and are inverse functions.

(a).

and .

(b).