If n is a positive integer then, (√3 + i)n + (√3 - i)n is
A. 2 n sin 6 n π
B. 2 n cos 6 n π
C. 2 n + 1 cos 6 n π
D. 2 n + 1 sin 6 n π
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A complex variable Z = x + j0.1 has its real part x varying in the range − ∞ to + ∞ . Which one of the following is the locus (shown in thick lines) of 1/Z in the complex plane?
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Integration of the complex function f ( z ) = z 2 − 1 z 2 , in the counterclockwise direction, around |z - 1| = 1, is
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If z is a complex variable, the value of 5 ∫ 3 i z dz is
A. -0.511 - 1.57i
B. -0.511 + 1.57i
C. 0.511 - 1.57i
D. 0.511 + 1.57i
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For the function z 3 sin z of a complex variable the point z = 0 is
A. a pole of order 3
B. a pole of order 2
C. a pole of order 1
D. not a singularity
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Let z be a complex variable. For a counterclockwise integration around a unit circle C, centered at origin.
∮ c 5 z − 4 1 dz = A π i the value of A is
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Let
j = − 1 . Then one value of j
j is
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The sum of residues of f ( z ) = ( z − 1 ) 2 ( z − 2 ) 2 z at its singular point is
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The value of the Integral c ∮ ( z 2 + 4 z + 5 ) − 3 z + 4 dz where c is the circle |z| = 1 is given by
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The value of C ∮ ( 1 + z 2 ) dz where C is the contour |z - i/2| = 1 is
A. 2πi
B. π
C. tan-1 z
D. πi tan-1 z
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The value of the integral ∮ z 2 − 4 z + 1 dz in counter clockwise direction around a circle C of radius 1 with center at the point z = -2 is
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The integral ∮ f ( z ) dz evaluated around the unit circle on the complex plane for f ( z ) = z cos z is
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The residues of a function f ( z ) = ( z − 4 ) ( z + 1 ) 3 1 are
A. 27 − 1 and 125 − 1
B. 125 1 and 125 − 1
C. 27 − 1 and 5 1
D. 125 1 and 5 − 1
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The value of expression 3 + 4 i − 5 + i 10 is
A. 1 - 2i
B. 1 + 2i
C. 2 - i
D. 2 + i
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The argument of the complex number
1 − i 1 + i , where
i = − 1 , is
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The nature of singularity of function f ( z ) = cos z − sin z 1 at z = 4 π is
A. Removable singularity
B. Isolated singularity
C. Simple pole
D. Essential singularity
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A point z has been plotted in the complex plane, as shown in figure below.
The plot for point
z 1 is
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The analytic function f ( z ) = z 2 + 1 z − 1 has singularities at
A. 1 and -1
B. 1 and i
C. 1 and -i
D. i and -i
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The values of the integral 2 π j 1 c ∮ z − 2 e z dz along a closed contour c in anti-clockwise direction for
i. the point z0 = 2 inside the contour c, and
ii. the point z0 = 2 outside the contour c, respectively, are
A. i. 2.72, ii. 0
B. i. 7.39, ii. 0
C. i. 0, ii. 2.72
D. i. 0, ii. 7.39
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Evaluate: c ∫ z sin z dz , where c is x2 + y2 = 1.
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