A.S=P+QL-QC B.S2=P2+Q2L-Q2C C.S2=P2+(QL-QC.2 D.S=P+QL+QC
A.16 B.8 C.4 D.2
A.φ1+φ2 B.φ1-φ2 C.arctan(X1+X2)/(R1+R2) D.arctan(X1-X2)/(R1+R2)