You can use Bode diagrams to study the stability of complete control systems but not the stability of isolated plants

The basic linear responses can be either stable or unstable, in both cases either with or without oscillations

Every transfer function with a second or higher order denominator will exhibit sinusoidal oscillations

A system is any physical magnitude whose evolution we can record over time

Every branch of a root locus will begin at a pole and end at at zero

The behavior of a unit system (copies input into output) is represented by the unit step

If we increase the gain of a main branch controller and the closed loop system is stable, the control system will be less sensitive to perturbations than with a lower gain

The contribution of a real zero to a Bode gain diagram begins asymptotically at its natural (cut-off) frequency and decreases 20 db per decade 

A set of equations represents a model of a system behavior

Root locus can be applied both to open loop and complete control systems but not for the same purposes