(a)

The formula is .

Let , then .

Differentiate with respect to .

Substitute and in the above equation.

.

Differentiate with respect to , then the above equation :

.

(b)

The formula is .

Let , then .

Differentiate with respect to .

Substitute and in the above equation.

.

Differentiate with respect to , then the above equation :

. 

(c)

The formula is .

Let , then .

Differentiate with respect to .

Substitute and in the above equation.

.

Differentiate with respect to , then the above equation :

.

(d)

The formula is .

Let , then .

Differentiate with respect to .

Substitute and in the above equation.

.

Differentiate with respect to , then the above equation :

.

(a) .

(b) .

(c) .

(d) .