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Complex Variables

                   for which the function f(z) is analytic               (c)  2x +      x    +
                                                                             −
                   is ______.                                                       x +   y 2  C
                                                                                      2
                               [GATE-2016-EC-SET 2]                                    y
                                                                         (d) 2xy −           +  C
                                                                                     2
            162.  What is value of the m for which                                  x +  y 2
                   2x x +  2  my  is harmonic?
                                 2
                       −
                                                                            [ESE 2017 (COMMON PAPER)]
                   (a) 1                 (b) -1
                                                                  165.  The value of     zdz  from z = 0 to z =

                   (c) 2                 (d) -2                                         c
                                                                         4 + 2i along the curve ‘c’ given by
                                                                           =
                                        [ESE 2017 (EE)]                  z t +  2  it
             CONSTRUCTION OF AN ANALYTIC                                          8i                     8
                                FUNCTION                                 (a) 10 −              (b) 10i +
                                                                                  3                      3

            163.  The real part of an analytic function                           8
                   f(z) where  z =  x +  jy  is given by                 (c) 10 −              (d) 0
                                                                                  3i
                   e − y  cos ( ) x . The imaginary part of
                                                                  166.  If z is a complex variable, the value
                   f(z) is                                                   3i
                                                                         of    dz
                                              −
                   (a) e  y  cos ( ) x    (b) e  y sin ( ) x                 5 z

                   (c)  e −  y sin ( ) x    (d)  e −  −  y sin ( ) x       (a) -0.511 – 1.57i

                                                                         (b) – 0.511 + 1.57i
                               [GATE-2014-EC-SET 2]
                                                                         (c) 0.511 – 1.57i
            164.  If W  =     i +   represents the
                   complex potential for an electric                     (d) 0.511 + 1.57i
                   field.
                                                                                     [GATE-2014-ME-SET 1]
                                             x
                                      2
                                 2
                   Given  =   x −   y +           , then
                                          x +   y 2               167.  Consider the line integral
                                            2
                                                                                          )
                                                                                         2
                   the function   is                                    I =    (   x +  2  iy dz , where z = x +
                                                                              c
                                  y                                      iy. The line c is shown in the figure
                   (a)  2x−  +         +  C                              below.
                                2
                              x +   y 2
                                 x
                   (b) 2xy +           +  C
                                2
                              x +   y 2







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