4. a. B is the image of A under a reflection in the B line y = x. If A is (x, f (x) ), find the coordinates of B. (1) A b. By substituting your result from a) into r y = f (x), show that f-'(f (x)) = x. (1) c. Using a similar method, show that VAVAVAHANNAY y=f(x) f ( f -1 ( x) ) =x. (2)