(a).

 (i).

The function is .

Therefore .

(ii).

Graph:

Graph of .

(iii).

The function is .

The definition of  hyperbolic trigonometry :  .

Substitute above value in .

.

.

Apply logirthm on each side .

.

Substitute  in the abovee expression.

(b).

(i).

The function is .

Therefore .

(ii).

Graph:

Graph of .

The function is .

The definition of  hyperbolic trigonometry :  .

Substitute above value in .

.

.

.

Therefore

Apply logirthm on each side .

.

 substitute in the above expression.

.

(c).

 (i).

The function is .

Therefore .

(ii).

Graph:

Graph of .

(iii).

The function is .

The definition of  hyperbolic trigonometry :  .

Rewrite the above function

Substitue above value in .

.

Apply logirthm on each side.

Substitue in the above equation.

.

(a).

(i).

(ii).

(iii).

.

(b).

(i).

(ii).

(iii)..

(c).

(i).

(ii).

(iii)..