Re-write the expression as

put in the above limit.

The limit is at undefined condition.Apply L-hospital rule.

put in the above limit

The limit is at undefined condition.Apply L-hospital rule.

.

put in the above limit

The limit is at undefined condition.Apply L-hospital rule.

put in the above limit

Therefore

Re-write the expression

put in the above limit.

The limit is at undefined condition.Apply L-hospital rule.

.

put in the above limit.

Therefore .