... H˜u,u Ðiê,n OLYMPIC TO´AN C´AC NU,´O,C1998 – 199957 Ð`Ê THI V`A L`O,I GI,AI(T.âp 1)NH`A XU´ÂT B,AN GI´AO D.UC20 Chu,o,ng 3. Ðê` thi olympic to´an ... thê,¯du,.o,c gi,ai quyê´t m.ôt c´ach d˜ê d`ang .14 Chu,o,ng 2. Ðê` thi Olympic To´an CanadaL`o,i gi,ai 2.3. Ch´ung tôi ch´u,ng minh r`˘angn(1 +13+ ... d.ang kh´ac(a, b) = (an+1, m2an+1− an) = (an+1, an+2).16 Chu,o,ng 2. Ðê` thi Olympic To´an CanadaNhu,ng sau¯d´o, c + a < a + a ≤ b + a, nhu,mong muô´n.T`u,nh˜u,ng¯diê`u...