The function is .

(a).

Slope of the secant line in terms of and is .

Find .

Substitute and in .

.

(b).

Find when .

Substitute the above values in .

.

Find when .

.

Find when .

.

As  approaches to zero approaches .

(c).

When then the slope of the secant line is .

.

The secant line containing the point .

Point - slope form of a line equation : .

Substitute and in point - slope form.

Secant line is .

For every linear function secant line is itself.

If is a linear function, every secant line coincides with the graph of .

Graph :

Graph of the function :

(a). .

(b). , when ;  ,  when ; when .

As  approaches to zero approaches .

(c). Secant line is .

(d). Graph of the function is