Question

Let a, b, c be three non-coplanar vectors and p, q r are vectors defined by the relations p = ((b × c)/[a, b, c]), q = ((c × a)/[a, b, c]) and r = ((a × b)[a, b, c]), the value of the expression (a + b).p + (b + c).q + (c + a).r is equal to 

(a) 0 

(b) 1 

(c) 2 

(d) 3

Answer 1

Answer is (d) 3

Explanation:

(a + b).p + (b + c).q + (c + a).r