where 2 is the only unknown angle. In this case, we can set i to be 1, and the result for 2
is 71.6.
When the angle of departure or arrival of a root locus for positive K at a simple pole or
zero of G(s)H(s) is determined, the angle of arrival or departure of the root locus for negative
K at the same point differs from this angle by 180, and Eq. (8-19) is now used. Figure F-7
shows that the angle of arrival of the root locus for negative K at 1 j is 108.4, which is
180 71.6. Similarly, for the root-locus diagram in Fig. F-8