A point performs damped oscillations with frequency \(\omega\) and damping coefficient \(\beta .\) Find the velocity amplitude of the point as a function of time \(t\) if at the moment \(t=0\) (a) its displacement amplitude is equal to \(a_{0}\); (b) the displacement of the point \(x(0)=0\) and its velocity projection \(v_{x}(0)=\dot{x}_{0}\).