Question

If cos-1 x cos-1 x/2 = , then 4x2 4xy cos + y2 is equal to

Answer 1

cos-1 x - cos-1 y/2 = alpha, then 4x2 - 4xy cos alpha + y2 = ? (a) 4 (b) 2sin2 alpha (c) -4sin2 alpha (d) 4sin2 alpha

Jawapan terbaik · 12 undi

We have, cos-1x - cos-1y2 = α⇒cos-1xy2 + 1-x21-y24 = α⇒xy2 + 1-x21-y24 = cos α⇒xy2