Question

If vector r = λ(a x b) + μ(b x c) + γ(c x a) and [a, b, c] = 1/8, then λ + μ + γ is

(A) 8(r.a)

(B) 8(r.b)

(C) 8(r.c)

(D) 8r.(a + b + c)

Answer 1

Answer is (C) 8(r . c)

Multiply the above relation with a, b, c, we have