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Question #41347
The Question
Let . A particle representing the complex number moves along the locus such that its imaginary part increases at a constant rate of units/sec. What is the rate of change of at the instant when ?
Options
- A.
-60
- B.
60
- C.
-68
- D.
68
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Monster
Ultra-high difficulty questions designed to test your limit, stamina, and deep conceptual understanding.
Concepts Behind This Question
Rate of Change Dependency|Rectangular Hyperbola|Geometry of Complex Inequalities
Why This Question Is Tricky
Common Mistakes
This question tests the intersection of complex loci geometry with differential calculus.
The core trap lies in the geometric constraint imposed by the complex inequality .
Students often mechanically solve and, upon seeing , default to the positive first-quadrant branch ().
If they use the positive branch, the chain rule yields , and the rate of change of becomes .
By enforcing the circle's interior condition, the problem strictly isolates the third-quadrant branch ().
This flips the signs of the coordinates but keeps the rates the same, resulting in a drastically different final value ().
Quick Facts About This Question
Question Information
| Subject | Mathematics |
| Chapter | Application of Derivatives - Class 12 |
| Concept | Rate of Change Dependency |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |