Odpowiedź:
A = ( 2 , - 1 ) , B = (- 3 , 2 ) , C = ( 1 , 1 )
xa = 2 , xb = - 3 , xc = 1 , ya = - 1 , yb = 2 , yc = 1
AB⇒ = [(xb - xa) , (yb - ya)] = [(- 3 - 2) , ( 2 + 1)] = [ - 5 , 3 ]
CA⇒ = [(xa - xc) , (ya -yc)] = [(2 - 1) , ( - 1 - 1)] = [ 1 , - 2 ]
AB + CA = [- 5 , 3 ] + [1 , - 2 ] = [ (- 5 + 1) , (3 - 2)] = [ - 4 , 1 ]
Odp: A
