Consider three points P(–sin(β – α), –cosβ), Q(cos(β – α), sinβ) and R(cos(β – α + θ), sin(β – θ)), where 0 < α, β, θ < π/4. Then
(a) P lies on the line segment RQ.
(b) Q lies on the line segment PR.
(c) R lies on the line segment QP.
(d) P, Q, R are non-collinear.
