Gthi cdc phuong trinh sau: a.. Tim gi6tnnh6 nhdt cria bidu thrlc: b.. Goi D ld giao didm cira EO vd BC.. Chtnrg minh AG lA tidp tuydn cira dudn,g trdn tAm O.. Cho hai ducrng trdn tdm O v
Trang 1rs PHoNG GrAo DUC vA ono rAo oGN cuAu
A
oE rnr cHeN Hgc srNH crdr HUyfr'N, Lop 9 voNG rr
NAM HQC 2013-2014
ivtON: Todn ( Thdi gian lhm bei 150 phrit)
Chul(4,O didd Gthi cdc phuong trinh sau:
a 3h+x+J-i=2;
b zJ*-t+Jz-* =zJi.
Cdu 2(4,0 didm) Gihi cdc hO phuong trinh sau:
^ l* +2xy-3x-3y-4=0.
= Y' +^l l1-(x+l)'
i.- J'
/I
= (y +l)2
CAu 3: (4,0 didd.
a Tim gi6tnnh6 nhdt cria bidu thrlc:
b Cho x,t,z le dQ dei 3 canh cira mot tam grdc, chrlng minh rang:
godi dudtng trbn thfing d khOng di qua O cit (O) tai B vd C(B nim gifra A
(O) tai B vd C c5t nhau tai E TU E ke EH vuOng g6c vdi
cung nh6 BC tai G Goi D ld giao didm cira EO vd BC
a Chung minh OH.OA = OD.OE;
-b Chtnrg minh AG lA tidp tuydn cira dudn,g trdn tAm O.
Ci 5(4,0 didm) Cho hai ducrng trdn tdm O vd tam O/ tidp xric ngodi tai I K6 tidp tuydn chung ngodi vdi (O) tai P vd vdi (O/) tai Q, cit ridp tuydn chung rrong It tai
K K6'c6c duong kfnh POP vd QC/Q/
I a Chrrng minh ba didm P, I, O thing hdng vd ba didm Q, I, P cfrng thing
hdng;
. b.jGoi S 1)r trung didm cira PQ/ Chung minh rang duirng thing PQ ld tidp
\-/ tuydn cira dudng trdn ngoai tidp tam gii{c SOO/.
tAm O Qua A k6 duong
vd C) Cr{c tidp tuydn vdi
AO( H ndm trOn AO) c6t
Hdt