PHONG GD&DT KY THI HQC SINH GIOI CAP QUAN V~NG 3 ~UAN LONG BZEN M6n : TOAN NIm hqc 2012-2013 Nguy thi: 31/01/2013 Thui gian lam bai: 150 phzit a) Rut gon biku thirc: A = 2\j4-\/5+\/21+480 0-Ji b) Tim chc gil tr/ ciia x di bi6u thirc sau c6 giii tri nguy&n M = 6 X+?&+Z Bai 2. (6 diim) 1. Giai cac phumg trinh sau: a) JZZT+x+l=~jx-2 b) ~~+iix+3=~-x-l-~ix+2+~~ 2. Timclcs6nguy~nxvaytho~mh: x2+xy-2010x-2011y=2012 Bii 3. (2 di&) Cho a > 0, b > 0 vh a + b 5 I. Tim giP tri lim nhAt cua bi&u thirc: a2b2 A= a4b2 + u2b4 i- a* + b2 a) Tim tit cachc b6 ba sanguydnta khbnhau a, b, c thohmh: abc = 3(a+b+c). b) Cho a;b la 2. s6 .guyen. Chimg minh rhg 5(a+b):+ab chia h6t cho 441 thi ab ciing chia hkt cho 44 1. Biii 5: (6 di&) Cho tam giac ABC vuBng tai A, (AB<AC) co dubng cao AH vB 0 la bung didm cGa BC. Duhng trbn th I dubng kinh AH cht AB, AC la11 luqt tai M vi N. a) Chimg minh : Tu giL BMNC nGi tiip. 1 1 1 b) Goi D II giao di&m clia OA va MN. Chhg minh - = - + - AD HB HC' c) Ggi P 18 giao di&m cda duhg thhg MN va dubng thing BC. Dvhg thhg AP cht dubng trbn duhg kinh AH tai di&m K (K + A). Tinh s6 do cua g6c BKC. d) Cho AB=6cm; AC=8cm . Tinh bhn kinh cGa duhg tron ngoai tikp tam gib BMN. Ch ti Ji: Gidm fhd coi fhi klr 8ng giai thich gi thin. Tkisinh n@p 11pi d$ thi srru klti tlii .vo~~g. Hr, ten thi sinh: SBD I . GD&DT KY THI HQC SINH GIOI CAP QUAN V~NG 3 ~UAN LONG BZEN M6n : TOAN NIm hqc 201 2- 2013 Nguy thi: 31/01 /2013 Thui gian lam bai: 150 phzit a) Rut gon biku thirc: A. diim) 1. Giai cac phumg trinh sau: a) JZZT+x+l=~jx-2 b) ~~+iix+3=~-x-l-~ix+2+~~ 2. Timclcs6nguy~nxvaytho~mh: x2+xy-2010x-2011y =2012 Bii 3. (2 di&) Cho a > 0, b >. Ch ti Ji: Gidm fhd coi fhi klr 8ng giai thich gi thin. Tkisinh n@p 11pi d$ thi srru klti tlii .vo~~g. Hr, ten thi sinh: SBD I