P. 417, line -9

The equation should be:

$\mathrm{\angle }G(s)={\tan }^{-1}\left(\frac{\mathrm{Im}kG(s)}{\mathrm{Re}kG(s)}\right)={\tan }^{-1}\left(\frac{k\mathrm{Im}G(s)}{k\mathrm{Re}G(s)}\right)={\tan }^{-1}\left(\frac{\mathrm{Im}G(s)}{\mathrm{Re}G(s)}\right),$

Return to errata.