The sufficient issue is that all The weather of the first column of the Routh array should have a similar indication. Therefore all The weather of the initial column on the Routh array really should be possibly good or unfavorable. With the Nyquist plots, we can easily discover whether the https://local.google.com/place?id=8622223340300826478&use=posts&lpsid=CIHM0ogKEICAgICO5LWcwgE