Answer each of the following questions in one word or one sentence or as per exact requirement of the question:

Show that .


Given LHS = sin-1 (2x - √ (1 – x2))


Let x = sin θ


= sin-1 (2sin θ √ (1 – sin2 θ))


We know that 1 – sin2 θ = cos2 θ


= sin-1 (2 sin θ cos θ)


= sin-1 (sin2 θ)


= 2θ


= 2 sin-1 x


= RHS


sin-1 (2x - √ (1 – x2)) = 2 sin-1 x


1