Solve::
Given, P(cosθ,sinθ)
and θ(cos(α−θ),sin(α−θ))
slope of (PQ);m=sin(α−θ)−sinθcos(α−θ)−cosθ
=−2sin(α2−θ)⋅cosα22sin(α2−θ)⋅sinα2
=−cotα2
slope of line or which is perpendicular
to PQ about which we take reflection
m2=tanα2
so, reflection of P in the passing through
origin with slope tanα2