Given, P(mcos2α,msin2α) and Q(mcos2β,msin2β) Distance
PQ=√(Difference of abscisse)2+(diff. of ordinates)2 √(mcos2β−mcos2α)2+(msin2β−msin2α)2 √m2(cos22β+cos22α−2cos2βcos2α)+m2(sin22β+sin22α−2sin2βsin2α) =√m2(cos22β+sin22β)+(cos22α+sin22α)−2(cos2βcos2α+sin2βsin2α)