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GATE 2026 MA – Question 38

Complex Analysis · Complex Integration and Residues · 2 marks · Multiple choice

Evaluate $\oint_\Gamma\frac{(1-z)(3\cos z+5\sin z)}{1-z^{101}}\,dz$, where Γ is |z| = 7/9, counterclockwise.

  1. $2\pi i$
  2. $-2\pi i$
  3. 0
  4. $4\pi i$

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Correct answer: (C) 0

Explanation

All zeros of 1−z¹⁰¹ have modulus 1, outside Γ. The numerator is entire, so the integrand is analytic throughout the disk bounded by Γ. Cauchy’s theorem gives **0, C**.

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