■2) Uk Zk 方=-站 Tk 2 Zk -Yk X (235+75) k75°c=k (235+0) 75e=Vr场5+x 2 9 9 ◼ 2) kk k IU z = 2kk k Ip r = 2 2 k k k x = z − r ( ) ( +  ) +  = 235 235 75 k 7 5 c k r r 2 2 k75 c k75 c k z = r + x  