a)
A(−1,2)
B(3,0)
S(2−1+3+ , 20+2)=S(1,1)
A1(1,2)
B1(−3,0)
S1(21+(−3) , 22+0)=S1(−1,1)
b)
A(−3,0)
B(3,4)
S(2−3+3+ , 20+4)=S(0,2)
A1(3,0)
B1(−3,4)
S1(23+(−3) , 24+0)=S1(0,2)
c)
A(−1,0)
B(5,3)
S(2−1+5+ , 20+3)=S(2,121)
A1(1,0)
B1(−5,3)
S1(21+(−5) , 20+3)=S1(−2,121)