$4$ points$)$ A unity negative feedback system has the open$-$loop transfer function L$($s$)=$ Gc $($s$)$G$($s$)=20$Ks$($s $+$ b$),$with K $>0$ and b $>0.$ Assume that the condition of the Final Value Theorem is satisfied. $(1$ point$)$ What is thetype number of this feedback system and why? Calculate the respective error constant and steady$-$state error ess $,$in terms of K and b$,$ for each of the following reference input signals $(1$ point for each case$)$