Thời gian làm bài: 180 phút !"#$(7,0 điểm) %&(2 điểm) x y x − = − !"#$% &'()#*+,- &'.# / %&(2 điểm) 0 !"#$% 1 2 3/ 4 x x x x π π + + = + + 05 !"#$%6 7 3 3 x x y x y x y x xy − + = − + = − %&(1 điểm)'899 :6,; 7 4 /< x x dx x π ∫ %&((1 điểm)' %= >/?@='?@<#&A#B?C?@;(D< #:BE>/FD G#>?@>?H#BCD G#'#=24 4 /89I #=#JD G#>?@>@/ %&('(1 điểm)((<K!"#LMNN;/O#$.#6 3 a b b c c a ab c bc a ca b + + + + + ≥ + + + (3 điểm)Thí sinh chỉ được làm một trong hai phần (phần A hoặc B) ) *+,-*./01230**&40 %&(5(1 điểm) 8$#D G#PQRS'+?-!T#G# ∆ 6SN3'N7;4/ 8 U PQ+@&Q!T#G# ∆ !T#G#?@ ∆ V C&#W7X 4 / %&(5(1 điểm6'8$#)A##C5PQRS'Y(+Z-[- !T#G# 6 3 x y z d + = = − − 7 \6 X x y z d − − = = O#6+Z(K(K]H#.$QD G#/ !"#^D G#=/ %&(5(1 điểm) 0 !"#^6 7 7 7 <# <# + + + + = x x x x x log x x x *+,-*./012780*%01-5, %&(9(1 điểm) 8$#D G#PQRS'!T#L_` 6 C x y+ = (!T#G# 6 4d x y m+ + = /8 U % m + C a d B?@K59#?@R<Cb/ %&(9(1 điểm) 8$#)A##C5PQRS'Y(D G#6 c6Sd'NYN;4(e6Sd'NYN3;4(f6SN'd3YN;4 !T#G# ∆ 6 − −x ; +y ; 3 z /0P ∆ <#&'ce/ !"#$%!T#G#K&A##=Cfa!T#G# ∆ ( ∆ / %&(9(1 điểm) 0b !"#$%6<# S <# 3 g S d1 ≤ [[[[[[[[[[F[[[[[[[[[[ %&':h8i S6 { } j D = ¡ h89 \ 4 y x D x − = < ∀ ∈ − F#$)# -−∞ - +∞ hF)A#=$ h0CB x Limy + → = +∞ x Limy − → = −∞ x Lim y →+∞ = x Lim y →−∞ = k=5iO#6S;(5i##'; h@# h %&':;8 &'B+ 4 4 - M x f x C∈ = !"#$% 4 4 4 \ y f x x x f x= − + F' 4 4 4 4x x y x x+ − − + − = h h#*+,- &'h.# 4 7 4 x x − ⇔ = + − #!V#5 4 4x = 4 x = i'6 &'l%6 4x y+ − = X 4x y+ − = %&':h@m !"#$%=!"#!"#C 3 4 2 4 2 c x x c x π − + + + = X 3 4 3 2 c x c x π π ⇔ + + + + = X 4 2 2 c x c x π π ⇔ + + + + = /0!V 2 c x π + = − 2 c x π + = − <B h0 2 c x π + = − !V#5 x k π π = + X 2 x k π π = − + %&':h@m5!"#!"#C 3 3 x xy x y x y x xy − = − − − = − hkDn I 3 x xy u x y v − = = (!V5 u v v u = − − = − h05$!V#5&-<6-4 [-[3h8*=#!V#5S-'<-4[-4 %&';<22=-,>?89K;[SKS(miS;4o;( 7 x π = % t = 8*= < <t t I dt dt t t = − = ∫ ∫ hkD < -u t dv dt t = = -du dt v t t ⇒ = = − >&'$ < < I t dt t t t = − + = − − ∫ hp& < I = − − %&@';(A*80* h0PF<$&#+@(O# SH ABC⊥ hqW##=#JD G#>?@(>?CD'< 4 24SEH SFH= = hr HK SB⊥ (<i <&i&'$#=#JD G#>?@>@.# HKA / hsi <&i9!V?;?@;( a HA = ( 4 3 24 a SH HF= = h8#>F&A#BF= 3 4 KH a HK HS HB = + ⇒ = h8#?F&A#BF= 4 3 3 4 a AH AK H KH a = = = 3 3 AKH⇒ = %&B6h@m a b c c ab c ab b a a b + − − = = + + − − − − h8*= c b a VT a b c a c b − − − = + + − − − − − − t((K!"#NN;((&Q)#4-;u[([([K!"# h KI#bG#OAK!"#!V 3 3/ / / c b a VT a b c a c b − − − ≥ − − − − − − ;3 kG#OS'$)E) 3 a b c= = = %&C5'h ∆ = !"#$% 3 x t y t = − = − + = 3-u = − ur h?&Q ∆ 3 - A t t⇒ − − + h8=?@- ∆ ;7X 4 - c AB u⇔ = uuuur ur / / AB u AB u ⇔ = uuuur ur ur X 3 2g X2 7X 4 3 3 t t t t⇔ − − = ⇔ = ∨ = − h+l%< 3 7 3 - ( - 3 3 3 3 A A− − %&D5';EKp& 4- -4M − = - - 3u = − − uur K]p& 4--7M = --Xu = uur h8= - 7- v-7u u O = − − ≠ uur uur ur ( 4--7M M = uuuuuuur qw - / 2 7 4u u M M = − + = uur uur uuuuuuur KK]# G#/ h0Pc<D G#OKK];ucW -- n = − ur p&Z = !"# $% 4x y z+ − + = htxb'+Z-[-&Qyc(*== %&F5'hkz&)56Su4 h8F6SwS;<#5 h8F6Sw x ≠ (m !"#$%!"#!"#C <# 7 <# 7 <# 7 x x x x x x + = + + + + + kD <# x x t+ = (!V !"#$%6 t t t + = + + #!V;;[{3 hC; <# x x⇒ + = !"#$%'A#5 hC;[{3 <# 3 x x⇒ + = − 3 /7 x x⇔ + = h |ib' v x = <#5h|& v x > %8hu |& v x < %8h}(i'h=#5K&'b v x = h<&i6#5 !"#$%=<S; v x = %&C9';E=:R4-4()9f;hKaB+ :5 - d O d⇔ < h8= / / / OAB S OAOB AOB AOB= = ≤ 8*=K59#?R@<Cb)E) 4 g4AOB = - d I d⇔ = m ⇔ = ± %&D9'h ∆ = !"#$% 3 x t y t z t = − = − + = h ∆ = !"#$% X 3 x s y s z s = + = + = h0~ -d A d B∩ ∆ = ∩ ∆ = - -3 @N-XN3-A t t t⇒ − − + h -3 2- 3 AB s t s t s t= + − + − uuuur (yf= -- 3n = − ur h •d R AB n⊥ ⇔ uuuur ur H# !"# 3 2 3 3 s t s t s t+ − + − ⇔ = = − 3 7 t⇒ = hKp& 3 - - v A = -- 3n = − ur ;uK= !"#$% 3 v 3 z x y − − − = = − %&F9';GH&IGJ06 3 4 <# g 1 4 g 1 4 x x x > − > − > #!V g <# 13x > % g <# 13x > u =!"#!"#C 3 <# g 1 x x− ≤ g 1 3 x x ⇔ − ≤ 3 v 3 g x x ≥ − ⇔ ≤ x ⇔ ≤ h<&ii #56 g <# 1-€T = . 3 - ( - 3 3 3 3 A A− − %&D5';EKp& 4- -4 M − = - - 3u = − − uur K]p& 4- -7 M = - -Xu = uur h8= -. + = + = h0~ -d A d B∩ ∆ = ∩ ∆ = - -3 @N-XN3 - A t t t⇒ − − + h -3 2- 3 AB s t s t s t= + − + − uuuur (yf= - - 3n = − ur h •d R AB n⊥. − h05$!V#5& ;- <6 -4 [ -[ 3h8*=#!V#5S-'< -4 [ -4 %&';<22 =-, >?89K;[SKS(miS;4o;( 7 x π = % t