Consider points A,B,C,D with position vectors 7^i−4^j+7^k, ^i−6^j+10^k, −^i−3^j+4^k and 5^i−^j+5^k respectively. Then ABCD is a
Show that the points A,B and C with position vectors, a=3^i−4^j−4^k, b=2^i−^j+^k and c=^i−3^j−5^k respectively, form the vertices of a right angled triangle.