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18   Chapter Onł









































                          Figure 1.5 Magnitude and direction of a vector in the complex plane.


                          Polar for of complex numbers
                          Consider the polar plane defined in termð of radiuð          r and angle
                            counterclockwise from the  a axis as shown in Fig. 1.7˜ The
                          expression for a Cartesian vector (a,b), representing the com-
                          plex number a   jb in polar coordinateð ( r, ) is obtained by
                          these conversions:

                                                             2
                                                                   2 1/2
                                                      r   (a   b )
                                                         tan   1  (b/a)

                          The expression for a polar vector (r, ) in Cartesian coordinateð
                          (a,b) is obtained by these conversions:

                                                        a   r cos


                                                        b   r sin

                          Therefore the following equation holds:
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