If C is a circle |z| = 4 and f ( z ) = ( z 2 − 3 z + 2 ) 2 z 2 , then c ∮ f ( z ) dz is
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What is the residue of the function z 4 1 − e 2 z at its pole?
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Let z = x + jy where
j = − 1 . Then
cos z = ? A. cos z
B. cos z
C. sin z
D. sin z
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Consider the function f(z) = z + z∗ where z is a complex variable and z∗ denotes its complex conjugate. Which one of the following is TRUE?
A. f(z) is both continuous and analytic
B. f(z) is continuous but not analytic
C. f(z) is not continuous but is analytic
D. f(z) is neither continuous nor analytic
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Consider the analytic function f(z) = x
2 - y
2 + i2xy of the complex variable z = x + iy, where
i = − 1 . The derivative f'(z) is
A. 2x + i2y
B. x2 + iy2
C. x + iy
D. 2x - i2y
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Using Cauchy's integral theorem, the value of the integral (integration being taken in counterclockwise direction) c ∮ 3 z − i z 3 − 6 dz is
A. 81 2 π − 4 π i
B. 8 π − 6 π i
C. 81 4 π − 6 π i
D. 1
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The value of the integral c ∫ ( 2 z − 1 ) ( z − 3 ) cos ( 2 π z ) dz (where C is a closed curve given by |z| = 1) is
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If the semi-circular contour D of radius 2 is as shown in the figure, then the value of the integral
D ∮ ( s 2 − 1 ) 1 ds is
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A harmonic function is analytic if it satisfies the Laplace equation. If u(x, y) = 2x2 - 2y2 + 4xy is a harmonic function, then its conjugate harmonic function v(x, y) is
A. 4y2 - 4xy + constant
B. -4xy + 2y2 - 2x2 + constant
C. 2x2 - 2y2 + xy + constant
D. 4xy - 2x2 + 2y2 + constant
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The complex function tan h(s) is analytic over a region of the imaginary axis of the complex s-plane if the following is TRUE everywhere in the region for all integers n
A. Re(s) = 0
B. I m(s) ≠ nπ
C. I m ( s ) = 3 n π
D. I m ( s ) = 2 ( 2 n + 1 ) π
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Let f1 (z) = z2 and f2 (z) = z be two complex variable function. Here z is the complex conjugate of z. Choose the correct answer.
A. Both f1 (z) and f2 (z) are analytic
B. Only f1 (z) is analytic
C. Only f2 (z) is analytic
D. Both f1 (z) and f2 (z) are not analytic
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If W = ϕ + i ψ represents the complex potential for an electric field. Given ψ = x 2 − y 2 + x 2 + y 2 x , then the function ϕ is
A. − 2 xy + x 2 + y 2 y + C
B. 2 xy + x 2 + y 2 y + C
C. − 2 xy + x 2 + y 2 x + C
D. 2 xy + x 2 + y 2 x + C
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An integral I over a counter-clockwise circle C is given by I = ∮ C z 2 + 1 z 2 − 1 e z dz .
If C is defined as |z| = 3, then the value of I is
A. -πi sin(1)
B. -2πi sin(1)
C. -3πi sin(1)
D. -4πi sin(1)
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The function f ( z ) = z 2 + 4 z 2 + 1 is singular at
A. z = ±2
B. z = ±1
C. z = ±i
D. z = ±2i
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If f(z) has a pole of order n at z = a, then Residue of function f(z) at a is
A. Res f ( a ) = ( n ) ! 1 { d z n − 1 d n − 1 ( ( z − a ) n − 1 f ( z ) ) } z = a
B. Res f ( a ) = ( n − 1 ) ! 1 { d z n − 1 d n − 1 ( ( z − a ) n − 1 f ( z ) ) } z = a
C. Res f ( a ) = ( n ) ! 1 { d z n − 1 d n − 1 ( ( z − a ) n f ( z ) ) } z = a
D. Res f ( a ) = ( n − 1 ) ! 1 { d z n − 1 d n − 1 ( ( z − a ) n f ( z ) ) } z = a
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Which one of the following functions is analytic over the entire complex plane?
A. cos(z)
B. e z 1
C. l n(z)
D. 1 − z 1
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Let z = x + iy be a complex variable. Consider that contour integration is performed along the unit circle in anticlockwise direction. Which one of the following statements is NOT TRUE ?
A. The residue of z 2 − 1 z at z = 1 is 2 1
B. ∮ c z 2 dz = 0
C. 2 π i 1 ∮ c z 1 dz = 1
D. z (complex conjugate of z) is analytical function
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An analytic function of a complex variable z = x + iy is expressed as f(z) = u(x, y) + iv(x, y), where
i = − 1 . If u(x, y) = 2xy, then v(x, y) must be
A. x2 + y2 + constant
B. x2 - y2 + constant
C. -x2 + y2 + constant
D. -x2 - y2 + constant
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Polar form of the Cauchy-Reimann equations is
A. ∂ r ∂ u = r ∂ θ ∂ v and ∂ r ∂ v = − r ∂ θ ∂ u
B. ∂ r ∂ u = r 1 ∂ θ ∂ v and ∂ r ∂ v = − r 1 ∂ θ ∂ u
C. ∂ r ∂ u = r 1 ∂ θ ∂ v and ∂ r ∂ v = − r ∂ θ ∂ u
D. ∂ r ∂ u = r ∂ θ ∂ v and ∂ r ∂ v = − r 1 ∂ θ ∂ u
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Let S be the set of points in the complex plane corresponding to the unit circle. (That is, S = {z : |z| = 1}. Consider the function f(z) = zz∗ where z∗ denotes the complex conjugate of z. The f(z) maps S to which one of the following in the complex plane
A. unit circle
B. horizontal axis line segment from origin to (1, 0)
C. the point (1, 0)
D. the entire horizontal axis
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