Before You Begin
Question #66383
The Question
Let and be the roots of the equation , with . Let be defined as . Consider the function defined by If , find the value of .
Options
- A.
28
- B.
14
- C.
40
- D.
-40
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Specialist
Targeted practice for niche, high-difficulty concepts that frequently appear in JEE Advanced exams.
Concepts Behind This Question
Limit Existence at Discontinuity|Composition Continuity|Quadratic Equations with Complex Coefficients
Why This Question Is Tricky
Examiner Levers
Recursive Logic
The answer to part A is required to solve part B (Step-wise failure test).
Difficulty Boost : +5Common Mistakes
This question tests the existence of limits for complex functions at a discontinuity when composed with a real-variable function.
The primary trap is that does not exist in the complex plane because the limit is path-dependent (it relies on the angle of approach).
Students might incorrectly conclude the limit does not exist or erroneously evaluate it along a standard path like the real axis (yielding 40).
However, because the inner function restricts the domain to , the approach to the discontinuity is locked along a specific line with direction .
This fixed phase shift must be accounted for, rewarding students who rigorously apply the definition of the composition rather than blindly applying L'Hôpital's rule or assuming path independence.
Quick Facts About This Question
Question Information
| Subject | Mathematics |
| Chapter | Continuity and Differentiability - Class 12 |
| Concept | Limit Existence at Discontinuity |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 170 sec |
| Access | Free |