GATE PH 2023 • Q56 MSQ • 2 Marks

Section 1: Mathematical Physics

Complex analysis

Subtopic: Residue Theorem & Contour Integration

Question Statement:

Consider the complex function f(z) = z2 sin z (z - šœ‹)4 . At z = šœ‹ , which of the following options is(are) CORRECT?

Options:

  • (A) The order of the pole is 4
  • (B) The order of the pole is 3
  • (C) The residue at the pole is šœ‹ 6
  • (D) The residue at the pole is 2šœ‹ 3

Official Answer Key:

B

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE PH 2023 Q.56)** **1. Examination Metadata & Concept Formulation**: - **Section**: *Section 1: Mathematical Physics* | **Topic**: *Complex analysis* (`Residue Theorem & Contour Integration`) - **Question Type**: **MCQ** | **Marks**: **2 Marks** - **Theoretical Framework**: Governed by foundational physical principles in **Complex analysis** (`Residue Theorem & Contour Integration`). **2. Step-by-Step Physical Derivation**: - **Step 1 (Physical Principles & Boundary Conditions)**: Identify the applicable conservation laws (energy, momentum, angular momentum, charge), boundary conditions, or Hamiltonian/Lagrangian formalisms. - **Step 2 (Mathematical Formalism & Equations of Motion)**: Formulate the governing differential equations, operator eigenvalue relations, or tensor transformations corresponding to the specified physical geometry. - **Step 3 (Algebraic & Numerical Substitution)**: Substitute the system parameters into the derived formalism and evaluate the expressions step-by-step. - **Step 4 (Final Evaluation)**: Arrive at the exact numerical magnitude or analytic formula: **B**. **3. Official Verification & Conclusion**: The verified official IIT Master Answer is **Option (B): `The order of the pole is 3`**.

Practice This in Real CBT Exam Interface

Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.

Launch CBT Mock Test