Question

Let a, b, c are three unit vectors, a + b + c = 0. Then a.b + b.c + c.a is

(a) –3/2

(b) 0

(c) –1

(d) 1

Answer 1

Answer is (a) -3/2

Explanation:

Given,

a + b + c = 0

(a + b + c)2 = 0