Bode Phase Plots

For phase, each factor is a complex number at any frequency, so phases can be treated individually:

$$\begin{array}{rl}\angle A(s)& =\angle \left(\frac{N_1(s)N_2(s)\dots }{D_1(s)D_2(s)\dots }\right)\\ & =\angle (N_1(s)N_2(s)\dots )-\angle (D_1(s)D_2(s)\dots )\\ & =\angle N_1(s)+\angle N_2(s)+\cdots -\angle D_1(s)-\angle D_2(s)\end{array}$$