例 3-2i 3-2i 3+2i(3+2i)(3-2)32+2 32 1313 3 √13 13 13 13 0=-arcts5 例 2 2 2 2 1 3 2 3 2 3 2 (3 2 )(3 2 ) 3 2 3 2 13 13 3 2 13 13 13 13 2 arctg 3 i i i i i i r − − = = + + − + = −     = + =           = −    