Page 24 - Calculus with Complex Numbers
P. 24

Ffgure 2./





















        Ffg ure 2.2



     a w-plane, andthen indicate how geometrical ligures inthe z-plane are transformed
     to geometrical ligures in the w-plane under the action of the function w = f (z).
       For example, for the complex function w = .:2 we find that the grid lines
     .x = corlstant y = constant in the z-plane transform to confocal parabolas in the
     w-plane (Figtlre 2.2).
       To see this observe that if z = .x + iy, w = u + i t? then


        u + iv = (x + ïy)2 = .x2 - ),2 + zj-xy,


     therefore


        Lf   2   2
          =   . Y  - #
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