$$

$4\mathrm{.}56$ A motor has transfer function H$($s$)=$ b$/[$s$($s$+$a$)]$ for known constants a$,$b $>0.($a$)$ Show that the step response blows up$.($b$)$ Showthat by using proportionalfeedback, the motor can be BIBO$-$stabilized $($c$)$ Show that if and only if K $=1,$ then the steady$-$state response error is zero.