I have a question, haven't been able to solve them..

PQ and PR are tangents to a circle with centre O,and A is any point on QR..PB is the perpendicular from P to OA produced and meets it at B..prove that the points O,Q,B,P,R,are concyclic..if QR or RQ produced meets PB produced at C,prove that qr is divided harmonically at A and C..