Question

1) If a b and c are vectors having
unit magnitude. If A + B +C = 0, then
AB+BC+CA will be -​
a) 1 b)-3/2 c)-1/2 d) 0

Answer 1

Answer:

(A+B+C)^2=0

THEREFORE EXPAND IT

THEN (A+B+C)^2-2(AB+AC+BC)

=(0)^2-2 (AB+BC+CA)

THEN AB+BC+CA=0