???? ??? ????? ?????? ????? ??????? ??????? ??????? ??????? ??????? ???? ?????? ??? ????????: ?² –??–?=? ???? ????? ????? ??????? ????? ????? ??????? ?????? ??? ??????? ???? ??????? ???? ??????? ???? ??????? ???? ??????? ???? ??????? ??? ????? ???? ????? ???? ???? ?????? ?? ?????????? ???? ???? ??????? ?????? ??????????? ???? ??? ?????? ?? ?