[r]
(1)d
TJBND TiNH TT{AI NGUYEN so crao ogc vA Dao T4.o
OE CUINII TIIUC
rf rru cHel{ Hec srNH GroI cAp riNn Lop e
I{AM HQC 201s-20r6
uON : roAN Hec
Thdi"gtan ldm bdi 150 philr ( Kh6ng kA tha gian giao di)
BAi Q diam)
Tfnh A : r/zot 52 +20!52.2016, +20162
-Bni2pdiam)
Chung minh (a+b)s = a8 +rlU*28a6b2 +56asb3 +70a4b4 +56a3bs +2gazb6 +gabi +bs
Bli 3 Q diam)
Chrmg minh 2'o +512 ld hgp s6
Bni 4 Q diem)
'f, Chrmg minh ring n6.t sO c6c c4nh ctra mQt tam gi6cvu6ng 1d c6c s6^
nguy6n thi sd hai c?nh g6c vuong khong th€ d6ng thdi le hai s6 16. Bei s Q diam)
Cho tam gi6c ABC c6 g6c d6u nhqn Gqi O ld t6m duong trdn ngoai titip, H
lA truc tdm, P ld trung di6m c?nh AC cua tam gi6c ABC.
a Chung minh BH: 2 OP
b Gqi L 1A trung di€m cira BH, chimg minh LP bing b6n kinh ducrng trdn
ngoai titip tam gi6c ABC Bni 6 @ di6m)
cho tam gi6c ABC c6 g6c BAC vu6ng, AB : AC, BC : a Tr6n BC I6y c6c diOm D vi E cho c6c g6c BAD, g6c DAE, g6c EAC beng
a Tinh DE theo a
b So s6nh BD v6i DE