If is equal to

(A) 4

(B) –8

(C) –4

(D) 8

## Solution:

Tip for solving this question:

Simplify the limit

Find value of

## Step 1 of 3:

Given,

On rationalisation, we get

## Step 2 of 3:

In

Here,

Now,

Here,

## Step 3 of 3:

Now,

## Final Answer:

Hence, Option (C) is correct.

Khushi says

Why is negative value of alpha taken? Nothing as such is mentioned in the question.

Plumsé says

in step 2 how’d you deduce that alpha is -ve and 1-alpha^2 = 0, it’s nowhere mentioned in the ques.

Pranam Jena says

because if alpha is positive then it is not indeterminate (infinite + infinite)form so alpha is taken as negative (infinite – infinite)