so cn-or HA riNnps cHiNu rHrlc Bdi 1.. Rut ggn bitiu thric F.. K6 ducrng thhng d lit ti6p tuy6n cria dudng trdn t4i H.. Tim gi6trinh6 nhAt d6 theo R.. Cho a,b,c ld crlc s6 thgc duong..
Trang 1so cn-or HA riNn
ps cHiNu rHrlc
Bdi 1 Rtit ggn:
oe rHr KHAO sAT cHAr Lr-IONG HQC KY r, LOp 9
NAM HQC 2014 - 20rs M6n: TOAN
(Thdi gian ldm bdi: 90 philt)
a P:2Jn -oJf 6 -D' .
11
b o=_; _ :,l
-lz I .,12 +l
Bdi2.Chobi€uthric,F:(S gl '-J voir)0, x+9.
[ /x+3 Jx-3) Jx
a Rut ggn bitiu thric F.
,1
b Tim x bi6t F =;.
Bni 3 Trong rn{t ph[ng to? d0 O,*y cho duong thdng d c6 phucrng trinh: y =(m-2)x+3m+6 (m +2)Timm d0 duong thdng r/di qua di6m M(-l; 3).
Bni 4 Cho duong trdn (O;R) vd H ld mQt diiSrn tr€n tludng trdn K6 ducrng thhng d lit
ti6p tuy6n cria dudng trdn t4i H Chc di€m A,B di dQng tr€n d tho6 mdn tan giitc AOB vu6ng tqi O Qua l, B vE chc fi6p tuy6n AE, BF cin (O;R) (E, F ld c6c tiep di€m) .
a Chring rninh: ZOAE = ZBOF
b X6c dinh vi tri cria A, B 1;1n d sao cho diQn tich tri gi6c ABFE dat giit tri nh6
nhAt Tim gi6trinh6 nhAt d6 theo R.
Bii 5 Cho a,b,c ld crlc s6 thgc duong Tirn gi6 tri l6n nh6t cria bi6u thric:
J,b Ji T-T- JA
a+b+2c b+c+2a c+a+2b
-11ft-Thi sinh kh6ng dugc str dpng tdi liQu.
Gituir th!kh6ng gi6i thich gi thOm.
Hg vd t6n thi sinh 56 b6o danh