Question

If a, b and c are non-coplanar vectors and p, q, r are defined as p = ((b × c)/[bca]), q = ((c × a)/[cab]), r = ((a × b)/[abc]), find the value of (a + b).p + (b + c).q + (c + a).r

Answer 1

We have, 

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

= 3