KY THI HQC SINH GIOI CAP QUAN V ~ N G M6n : TOAN NIm hqc 2012-2013 Nguy thi: 31/01/2013 Thui gian lam bai: 150 phzit PHONG GD&DT ~UAN LONG BZEN a) Rut gon biku thirc: A = 2\j4-\/5+\/21+480 0-Ji b) Tim chc gil tr/ ciia x d i bi6u thirc sau c6 giii tri nguy&n M = X+?&+Z Bai (6diim) Giai cac phumg trinh sau: a) J Z Z T + x + l = ~ j x - b) ~~+iix+3=~-x-l-~ix+2+~~ T i m c l c s n g u y ~ n x v a y t h o ~ m hx2+xy-2010x-2011y=2012 : Cho a > 0, b > v h a + b I Tim giP tri lim nhAt cua bi&uthirc: Bii (2 di&) A= a2b2 a4b2+ u2b4i- a* + b2 a) Tim tit cachc b6 ba sanguydnta khbnhau a, b, c t h o h m h : abc = 3(a+b+c) b) Cho a;b la s guyen Chimg minh r h g 5(a+b):+ab chia h6t cho 441 thi ab ciing chia hkt cho 44 Biii 5: (6 di&) Cho tam giac ABC vuBng tai A, (AB