TRUONG THPT BA.O DUY Tit Mt .?\\~ ~ '-<;;)f~ (OOJ BE THI TOO B~I HQC BQ'T VI (2008 - 2009) MoD: TOA.N; Kh8i A. Thai gian lam hai: 180philt, kh6ng kd thai gian phat dJ * * * ------------ Can I. Choham s6 y = x3 +ax2 +bx+c. 1. Khflosat S\1'bi€n thien va ve db thi cua ham s6 khi a = 3,b = 0, c = -4 . 2. ChUngminh r~ng di~u ki~n cAnva du d€ db thi ham s6 c~t tI1)Choanh t~i hai di€m d6i xung nhau qua g6c tQadQla ab = c v6'i b < O. Can II. 1. Gifliphuang trinh: 1+ 2 .Jx - x2 = -rx + .J1- x . 3 2. Gifliphuang trinh: sin2x+ sin23X(cOS3xsin3x+sin3xcos3x)=sinxsin23x. 3sin4x . 2 C " III Tinhd "" , hhinh h ~ d "' h b '. , d ' 2 x , 27 an. I~ntIC p ang uQ'cglal ~ 01cac uang y = x ,y = 8 va y =--;. Can IV. Cho tU di~n ABCD, trong d6 BC = a, AB = AC = b, DB = DC = c, a la g6c ph~ng OOidi~n c~nh BC (a < ~). V6'i di~u ki~n nao cua b, c thi duemg th~g n6i trung di€m E ctia BC vai trung di€m F ctia AD la duemgvuong g6c chung ctia BC va AD? V6'idi~uki~n vila tim duQ'chay tiOOth€ tich tUdi~n ABCD. Can V. Cho x, y, z la ba s6 duang th6a man xyz = 1. ChUngminh r~g: x2 y2 z2 3 -+-+-;;::-. l+y l+z l+x 2 Can VI. Trang khong gian v6'i h~tQadQl)~ cac vuong g6c Oxyz cho m~t cAll x2 + y2 + z2 = 4 (8) vam~tph~g x+z=2 (P). 1. Chung minh r~ng m~t ph~ng (P) c~t m~t cAll(8). Xac dinh tQadQtam va tinh ban &im ctia duemgtrim (C) la giao tuy€n gifi'a(P) va (8). 2. Vi€t phuang trinh duemg cong (CI) la hinh chi€u vuong g6c ctia (C) tren m~t ph~ng tQadQOxy. Can VII. Tu cac chfi's6 1, 2, 3, 4, 5, 6, 7, 8, 9 c6 th€ l~p duQ'cbaa nhieu s6 t\1'nhien m6i s6 gbm 6 chfi' s6 khac nhau va tAng cua cac chu s6 hang chl,lc,hang tram, hang nghin b~ng 8? Giam thi coi thi kh6ng giai thiGhgi them ---------------------- ( . thai gian phat dJ * * * -- -- - -- - -- - - Can I. Choham s6 y = x3 +ax2 +bx+c. 1. Khflosat S1'bi€n thien va ve db thi cua ham s6 khi a = 3,b = 0, c = -4 . s6 hang chl,lc,hang tram, hang nghin b~ng 8? Giam thi coi thi kh6ng giai thiGhgi them -- -- - -- - -- - -- - -- - -- - -- (