If  is finite then the values of a,b are respectively

The correct answer is:

In this question we are given that the limit  of this expression is finite and we have to find the value of  and 
Step1: Putting the value of the limit
By putting the value of limit the denominator of the expression tends to zero. In order for the limit to exist the numerator must also tend to zero.

by putting  we get,

=>
As we are getting  form. We will use L'Hôpital's rule
Step2: Using the L'Hôpital's rule
By differentiating both numerator and denominator.
=> 
By putting the value of limit, we are getting both numerator and denominator as zero.
So, we will again apply L'Hôpital's rule

By putting the value of limit the denominator tends to  zero. For the limit to exist the numerator must also tend to zero.

=>
=>
Then 
.
So, the value of  and  are