Q21. Compute ∫ cos(z/2) dz, over (0, π + 2i).
A e + 1/e
B sin (π/4)
C 2πi
D 0
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Correct answer: e + 1/e
Q22. Cauchy's residue theorem is used to solve:
A Initial value problems
B Boundary value problems
C Integral in complex domain
D Integral equations
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Correct answer: Integral in complex domain
Q23. Necessary condition for an arc z = z(t) (a ≤ t ≤ b) to be smooth, is a:
A Continuous z′(t)
B Integrable z(t)
C Differentiable z(t)
D Harmonic z(t)
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Correct answer: Continuous z′(t)
Q24. Residue of complex valued function 1 zcos at z 0 is: z
A 1/4
B 1/3
C 1/2
D 1
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Correct answer: 1/2
Q25. The transformation az b w cz d with complex constants a, b, c, d makes a bilinear transformation when:
A ad – bc = 0
B ad – bc ≠ 0
C a b/d c
D a b/d c
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Correct answer: ad – bc ≠ 0
Q26. In the Laurent series expansion of the function f(z) = 1 1 –, z –1 z – 2 valid in the region |z| > 2, the coefficient of 2 1 z is
A 0
B 1
C – 1
D 2
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Correct answer: – 1
Q27. For f (z) = z 4 e sinhz z, the residue at z = 0 is
A 2/3
B 1/3
C 1/2
D 1/6
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Correct answer: 2/3
English UPPSC Polytechnic Lecturer 2021 (I)
Q28. The value of the integral ∫ 3 z =1 1 1 z cos dz 2πi z is equal to
A 0
B 1
C 1 – 6
D 1/24
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Correct answer: 1/24
English UPPSC Polytechnic Lecturer 2021 (I)
Q29. The residue of the function f(z)= sinz zcosz at the pole z= π 2 is -
A 0
B 1
C 2 – π
D 2/π
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Correct answer: 2 – π
English UPPSC Polytechnic Lecturer 2021 (I)
Q30. Consider the function f(z)= 2 1. z sinz Which of the following is correct?
A f has pole of order 1 at z = 0
B f has pole of order 2 at z = 0
C The residue of f at z = 0 is 1 3
D The residue of f at z = 0 is 1 6
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Correct answer: The residue of f at z = 0 is 1 6
English UPPSC Polytechnic Lecturer 2021 (I)
Q31. Consider the following statements- I. z 2 e f(z) = z is meromorphic in C II. f(z)=(z2 –4)–1 1 sin is z meromorphic in C then
A I and II both are true
B I and II both are false
C I is true but II is false
D II is true but I is false
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Correct answer: I is true but II is false
English UPPSC Polytechnic Lecturer 2021 (I)
Q32. The principal part of the Laurent series of 1 f(z) = z(z –1)(z – 2) in the annulus { } z:0 < z < 1 is -
A 1 – z
B 1/z
C 1 – 2z
D 1/2z
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Correct answer: 1/2z
English UPPSC Polytechnic Lecturer 2021 (I)
Q33. Let C be a circle 3 z = 2 that is oriented in the counter clockwise direction. The value of 'a' for which C ∫ 2 z +1 a + dz = 0 z – 3z + 2 z –1 is-
A 1
B –1
C 2
D –2
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Correct answer: 2
English UPPSC Polytechnic Lecturer 2021 (I)
Q34. If f(z) is analytic in circle C: z – a < r and if ≤ f(z) M on C, then-
A n! r =
B (n) n M f
C (n) n M f
D None of the above
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Correct answer: n! r =
English UPPSC Polytechnic Lecturer 2021 (I)
Q35. The coefficient of 1 z –1 in the Laurent's series expansion of () z 2 e z –1 about z=1 is-
A 1
B e
C 1/e
D 0
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Correct answer: e
English UPPSC Polytechnic Lecturer 2021 (I)
Q36. If C is the unit circle z = 1, ()() C ∫ 2 z 2z +1 z + 2 dz is equal to-
A 4 i/π
B 8 i/π
C i 6 π
D i 12 π
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Correct answer: i 6 π
English UPPSC Polytechnic Lecturer 2021 (I)
Q37. The value of the integral ∫ 2π 0 dθ 3 + 2cosθ is-
A 2 5 π
B 5/π
C 2 5/π
D None of these
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Correct answer: 2 5 π
English UPPSC Polytechnic Lecturer 2021 (I)
Q38. The order of a canonical product P(z) is equal to-
A Convergence exponent of its zeros
B Convergence exponent of its poles
C 1 always
D None of these
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Correct answer: Convergence exponent of its zeros
English UP Higher Asst. Prof. 2021
Q39. A function f(z) has no singularity in the finite part of the plane but has a pole of order m at infinity. then,
A f(z) is a polynomial of degree m.
B f(z) has zero of order m.
C f(z) has singularity.
D None of these
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Correct answer: f(z) is a polynomial of degree m.
English UP Higher Asst. Prof. 2021
Q40. Value of integral ()() 2 c zdz 9 z z i − + ∫, where C is the circle z 2 = (Using Cauchy's integral formula) equals to,
A π/2
B π/3
C π/5
D π/7
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Correct answer: π/5