[r]
(1)UBNI}Tn{I{THAINGUYENx?rmCHQNHQCSINEIclorcarrixulorrr so crAo pUC & pAo'r4to xam HQC 2013 - 2014
nm cninu rntfc wION : ToAN Hgc
Thdi sian: - t 50 phtit (kh6ng fA inat gian giao di)
(DA thi gdm cd, 01 trang)
tsailkidia@'
r t 2n\ ( z,r\
a)Giaipkrumrgtrinh: cos3x+ ' =1+4cosl x +! icosl .x '- l .oir*'''"""t )/ '' 3J
b) Cho phucrng trinh: ax' +(e + c)r + {a + r) = 0 (t) ce m$t nghiQm kh6ng
nh6 h.ryn Chrmg minh rang phuong trinh axo +bx3 +cx'+dx+e-$ (Z) c6 nghiQrn,
BAi
'(4 di6w)
Ciro d6y s0 (r, ), ^ x6o dfnh nhu sau:
lro,o
t,
1r,,-, = ;(,'; + s)
vur > o'
-K6c dinh tdt ch"ac gii trf duong crla xo cho day cta cho ed gi6i han
Lrftu h7n
tsAi ft di€rn)
Cjno trt diOn S,4^B C a6 SI,,SB,,SC d$i inOt vu6ng g6c vdi nhau" Gqi F/ vh O
ldn luct th truc tdm vh tam du&ng trdn ngoai tidp tam gi6c ABC ' Chfug minh rdng:
(ort)' ^ I
l
I + /
= _ _ -Isru ) - 4coslcr:sBcosC Bei 4 (3 Ci6m)
r:o 72 p4 76 C?Yt
Tfrilr tdng: - = e'ue - !-z'qt+ * -Y2gtt +:2q+ + "" :' -
jsu.-ll- * ;"{ * - t 42 ' "7 .4j ' 2015.4t002
'
Bii 5 (3 di:6m)"
Cho c; b;r >0 thoa rn&n a + b + c + abc= 4 " Chirng minh rEng:
a J -.: b l'''
^fr, +, J, + r*7f17=t;