VITEEE 2014 Paper

r.a = α (a.b × c) + β (a.c × a) + γ (a.a × b) = a [a b c] + 0 + 0
Similarly, r.b = β [a b c] and r.c = γ [a b c]
∴

1

2

r . (a + b + c) =

1

2

(r.a + r.b + r.c)
=

1

2

(α + β + γ) [a b c]
=

1

2

(α + β + γ) × 2 = α + β + γ