Given f(z) = g(z) + h(z), where f, g, h are complex valued functions of a complex variable z. Which one of the following statements is TRUE?
A. If f(z) is differentiable at z0 , then g(z) and h(z) are also differentiable at z0
B. If g(z) and h(z) are differentiable at z0 , then f(z) is also differentiable at z0
C. If f(z) is continuous at z0 , then it is differentiable at z0
D. If f(z) is differentiable at z0 , then so are its real and imaginary parts
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All the values of the multi-valued complex function 1
i , where
i = − 1 , are
A. purely imaginary
B. real and non-negative
C. on the unit circle
D. equal in real and imaginary parts
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If f(x + iy) = x
3 - 3xy
2 + i
ϕ (x, y) where
i = − 1 and f(x + iy) is an analytic function then
ϕ (x, y) is
A. y3 - 3x2 y
B. 3x2 y - y3
C. x4 - 4x2 y
D. xy - y2
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Potential function ϕ is given as ϕ = x2 - y2 . What will be the stream function ψ with the condition ψ = 0 at x = y = 0?
A. 2xy
B. x2 + y2
C. x2 - y2
D. 2x2 y2
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Consider likely applicability of Cauchy's Integral Theorem to evaluate the following integral counter clockwise around the unit circle c.
I = c ∮ sec z dz, z being a complex variable. The value of I will be
A. I = 0 : singularities set = ϕ
B. I = 0 : singularities set = { ± 2 2 n + 1 π ; n = 0 , 1 , 2 ... }
C. I = 2 π : singularities set = { ± n π ; n = 0 , 1 , 2 ... }
D. None of above
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For a complex number z = 1 - 4i with
i = − 1 , the value of
z − 1 z + 3 is
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The value of the contour integral ∣ z − i ∣ = 2 ∮ z 2 + 4 1 dz in positive sense is
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The value of
∮ Γ ( z − 1 ) ( z − 2 ) 3 z − 5 dz along a closed path
Γ is is equal to (4πi), where z = x + iy and
i = − 1 . The correct path
Γ is
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The contour integral C ∮ e z 1 dz with C as the counter-clockwise unit circle in the z-plane is equal to
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A complex function f(z) = u(x, y) + iv(x, y) and its complex conjugate, f'(z) = u(x, y) - iv(x, y) are both analytic in the entire complex plane, where z = x + iy and
i = − 1 . The function f is then given by
A. f(z) = x + iy
B. f(z) = x2 - y2 + i2xy
C. f(z) = constant
D. f(z) = x2 + y2
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The complex number ( 3 − i 2 + i ) 2 is
A. 2 1 ( cos 4 π + i sin 4 π )
B. 2 1 ( cos 2 π + i sin 2 π )
C. 2 1 ( cos π + i sin π )
D. 2 1 ( cos 6 π + i sin 6 π )
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The residues of a complex function X ( z ) = z ( z − 1 ) ( z − 2 ) 1 − 2 z at its poles are
A. 2 1 , − 2 1 and 1
B. 2 1 , 2 1 and − 1
C. 2 1 , 1 and − 2 3
D. 2 1 , − 1 and 2 3
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Which one of the following functions is analytic in the region |z| ≤ 1?
A. z + 2 z 2 − 1
B. z + j 0.5 z 2 − 1
C. z z 2 − 1
D. z − 0.5 z 2 − 1
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The value of the integral ∮ ( z − 2 1 ) ( z 2 − 4 z + 5 ) 2 z + 5 dz over the contour |z| = 1, taken in the anti-clockwise direction, would be
A. 13 24 π i
B. 13 48 π i
C. 13 24
D. 13 12
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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) = x
2 - y
2 , then expression for v(x, y) in terms of x, y and a general constant c would be
A. xy + c
B. 2 x 2 + y 2 + c
C. 2xy + c
D. 2 ( x − y ) 2 + c
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The residue of the function f ( z ) = ( z + 2 ) 2 ( z − 2 ) 2 1 at z = 2 is
A. − 32 1
B. − 16 1
C. 16 1
D. 32 1
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For a complex number z, z → i lim z 3 + 2 z − i ( z 2 + 2 ) z 2 + 1 is
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The residue of f ( z ) = ( z − 1 ) 4 ( z − 2 ) ( z − 3 ) z 3 at z = 3 is
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Given f ( z ) = z + 1 1 − z + 3 2 . If C is a counter clockwise path in the z-plane such that |z + 1| = 1, the value of 2 π j 1 ∮ C f ( z ) dz is
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If a complex number ω satisfied the equation ω3 = 1 then value of 1 + ω + ω 1 is
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