(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). .