যদি a cos α+b sin α=acos β +bsin β হয়, তবে দেখাও যে, cos2α+β2-sin2α+β2=a2-b2a2+b2.(If a cos α+b sin α=acos β +bsin β, then show that cos2α+β2-sin2α+β2=a2-b2a2+b2.)