(a)

The expression is .

The numerator and denominator approach to infinity as  tends to infinity.

Consider .

Divide both the numerator and denominator by .

Simply the above expression.

As then .

Therefore, .

(b) 

.

The numerator and denominator approach to infinity as  tends to infinity.

Divide both the numerator and denominator by .

Simply the above expression.

As then .

Therefore, .

(c) 

.

The numerator and denominator approach to infinity as  tends to infinity.

Divide both the numerator and denominator by .

Simply the above expression

As then .

Therefore, .

(a) .

(b) .

(c) .