JEE Main20199 Jan 2019Morning ShiftMathematicsLimitsActual
The value of l i m y → 0 1 + 1 + y 4 - 2 y 4
Options
- Aexists and equals 1 2 2
- Bexists and equals 1 4 2
- Cdoes not exist
- Dexists and equals 1 2 2 2 + 1
Correct answer
B. exists and equals 1 4 2
Step-by-step solution
To solve this question, we need to apply the concept of rationalization twice. Given limit is l i m y → 0 1 + 1 + y 4 - 2 y 4   (   0 0   form ) = l i m y → 0 1 + 1 + y 4 - 2 y 4 × 1 + 1 + y 4 + 2 1 + 1 + y 4 + 2 = l i m y → 0 1 + y 4 - 1 y 4 1 + 1 + y 4 + 2 × 1 + y 4 + 1 1 + y 4 + 1 = l i m y → 0 y 4 y 4 1 + 1 + y 4 + 2 1 + y 4 + 1 = l i m y → 0 1 1 + 1 + y 4   + 2 1 + y 4 + 1 = 1 4 2 .