481 Apppridix A Solintions to t hc Excrcises -52s FIQIXI II(s) s3 -t 4s2 + 52 we deterrriiiir the system cliffe~ciitial(qiiat ioir + _aos + 52 a) T l i c signal i s also i-lheatly liiiown before i = 0, so it is not, an initial x-alw problen1 t,) It i s Y ( s )= I$(s) S ( s ) with I R.c{.s} > -1 H(s) = 1’ - _ (6 - + 1)(.++ d;) + A - - s t s B +JW() + -1 ( s+ l)(S B4 + -.s +2)2 + -s cs + -s Dc + ( S lI?L -2)