Thời gian làm bài 180 phút Câu I (2 đim)!""#$%& ' ' ( ) y x x m x= + + + + *+,-."/0#( $ ) ! "1%.2#23,-."/"#$%&4"5$6! ! 7$"8995.:/*;<$,=,>?9."@9 y x= + *A.,-."/( $ ).B5',5=$C"DE5F.(G)HIH %<*"**.5JC.KLJ*;<( $ ).B5I2#2K99+*2M5"<K! Câu II (2 đim)! 1. 515"FC">N9.:7" ' ' ' ' x y y x + − = + − = 2. 515C">N9.:7" *% ( %5O)( .< ) %5O *% x x x − − + = − Câu III (2 đim) ! P"."=.P*"2Q.."=.:RO<L%5":<4"5SK<L"7"C"@995M5"BET5,>?9.:R.D$(G)E 4P"U6SK<".:V*"#"! ! :94"995<*""<5,5=$HI*&,/"H,WX#5,BI6<Y!O2#IL0#"<5Z< ,>?9."@92K99+*2M5"<K2#*[92K99+*2M5I!:\O2#IL0]L"<5,5=$2#%< *"6E(2M5E0#$W.%&*".:>M*2#EY<)! <) ^*,/".D$2#E4P"$_.*`K9B5.5JC.aX5FI! E) ^*,/"2/.:P*;<2#%<*".aX5FI*+."=.P*"0M"].! Câu IV (1 đim).7$$,=E].C">N9.:7"%<K*+9"5F$ ' ( ) ( ) x m x m x+ ≥ + + − + ! bMỗi thí sinh chỉ chọn câu Va hoặc Vb Câu Va (3 đim)!Chương trình cơ bản ! :9$_.C"@9.c<,WOLH*",5=$('G)2#"<5,>?9."@9*+C">N9.:7"0# d x y− + = 2# ' d x y+ − = !d5J.C">N9.:7",>?9."@9,5SK<2#.B2M5"<5,>?9 ."@9 #d v d $W..<$95**D*+,e"0#95<,5=$*;< #d v d ! ! :94"995<2M5"F.c<,WOLfH*""<5,>?9."@9 x y z− + − ∆ = = − ' x y z+ − − ∆ = = − 2#$_.*`K( )O gL gf ghOiLgjfgk6!d5J.C">N9.:7"$_. C"@9.5JCOl*2M5$_.*`K( ),-9."?5%9%92M5 ∆ 2# ∆ ! '! 7$C"`."m**;<%&C"a* ( ) n i− Câu Vb. (3 đim).Chương trình nâng cao ! :9$_.C"@9.c<,WOLH*""LCoE0 ( )H *+C">N9.:7" x y a b − = 2#0#,5=$E].4p ."KW*()!c5X HX 0#**,>?9."@9,5SK<2#%9%92M5**,>?9.5F$*Q*;<()! "a9$5":q9"7"E7""#".BET5X HX 2#**,>?9.5F$*Q*;<()*+X5F.P*"4"9,r5! ! :94"995<2M5"F.c<,WOLfH*"',5=$(G'Gi)HI(GG)H(GG)!7$.c< ,W*;<,5=$%<*" gI g ,B.95.:/"s"].! '! 515E].C">N9.:7" h Hk j 09 h09 h 09x x x+ ≤ − tJ.t (EW*5."54"99515."P*"97."\$) uuv DK w W5XK9 5=$ ^x6 ¡ mE5J."5\Ly6'O gjOg'6'(Og) x ≥ ∀ ∈ ¡ #$%&,-9E5J.:\ ¡ #$%&4"9*+*m*.:/ 5M5"B 05$ x y →±∞ = ±∞ I19E5J."5\ O −∞ +∞ Ly gg L +∞ −∞ -."/ L i O k ' k k ">N9.:7""#",W95<,5=$*;<,-."/( $ )2#,>?9."@9L6Og O ' g'O g$O6 ' x x x m = ⇔ + + = >?9."@9L6Og*A.,-."/( $ ).B5',5=$C"DE5F.4"52#*"e4"5 ( ) ' g x x x m= + + = *+"<59"5F$C"DE5F.4"*4"52#*"e4"5 n n h h () m m g m m ∆ > − > < ⇔ ⇔ ≠ ≠ ≠ (z) "5,+"#",W*;<I2#."s<${ ' ! B C B C x x x x m + = − = () <*+|y(O)6'O gjOg$g F%&9+***.5JC.KLJ.B5I2#0#|y(O I )6 ' j B B x x m+ + + H|y(O )6 ' j C C x x m+ + + *.5JC.KLJ.B5I2#2K99+*4"52#*"e4"5|y(O I )!|y(O )6i ⇔ ( ' j B B x x m+ + + )!( ' j C C x x m+ + + )6i ⇔ ( ' j B B x x+ )( ' j C C x x+ )g($g)( ' j B B x x+ g ' j C C x x+ )g($g) 6i ⇔ n( ! ) } ( ) 'j '( )(( ) ( )) B C B C B C B C B C B C B C x x x x x x x x m x x x x x x+ + + + + + − + + g$ g$g6 J."~C2M5().<,>~* n$ •kh$g'j$g'($g)(n•$i')g$ g$g6 ⇔ h$ •'$g6C">N9.:7"29"5F$! dQL4"9*+95.:/*;<$."s<${L\K*`K! k k k k 5€K45F 'H 'x y≤ ≤ ≤ ≤ <*+ ' ' ' ' x y y x + − = + − = ⇔ (' ) (' ) x y x y y x y x − + − = − + − = (' ) (' ) (' ) (' ) x y y x x y y x ⇒ − + − = − = ⇔ − = ⇔ ' ' x y x y = = = = 5=$.:<.<."]L ' H ' x x y y = = = = ."s<${! J.0KQF*+"F*+"<59"5F$ ' H ' x x y y = = = = k k k k 4 %5O *% *% x x ≠ ≠ ! ">N9.:7".>N9,>N92M5 ( %5O) *% ( %5O) *% % %5O *% %5 %5O *% *% (%5O *% ) ( %5O)( *% ) %5O %5O *% %5O *% %5O!*% (%5O )(*% ) %5O *% x x c x x x x x x x x x x x x − − − − = ⇔ = − − − − ⇔ = ⇔ − = + − + − ⇔ − + − = ⇔ − + = = ⇔ = − g)%5O64"9."s<${4274"5,+*%O6! g)*%O6i Hx k k π π ⇔ = + ∈¢ ."s<${! J.0KQ">N9.:7"*+"c9"5F$ Hx k k π π = + ∈¢ k k k k >?9.:R.D$(G)E4P"U6*+C">N9.:7"(Oi) g(Li) 6 5€K45F 'x≤ ≤ !•C">N9.:7",>?9.:R.<*+ ( )y x= + − − 2M5 y ≥ d# ( )y x= − − − 2M5 y < ! "=.P*"2Q.."=*`.7$ ( ) ( ) ' ' ' ( ) ( ) } ( ) V x dx x dx x dx π π π = + − − − − − − = − − ∫ ∫ ∫ _.O•6%5.2M5 x π π − ≤ ≤ ! k k O6 ⇒ .6 π − O6' ⇒ .6 π XO6*%.X.H ( )x− − 6*%.! dQLd6 } %c tdt π π π − ∫ 6 h ( % ) hc t dt π π π π − + = ∫ k k <) c50#.:K9,5=$*;<! <*+ HBN AB BN AM BN BM⊥ ⊥ ⇒ ⊥ O X,+.<$95*I2K9.B5I%KL:<I6 MN H .>N9.m6 MN ! dQL6I666 MN 6 b D$$_.*`K9B5.5JC0#HE4P"U6 b I E)_.6OYHI6LY <$95*I2K9.B5I\ 6I gI L <$95*2K9.B5\ 6 g KL:<E 6 6 gI gI 6O g< gL x,+O gL 6E •< 4"9,r5! aX5FI*+,L0#IH,>?9*<I! "=.P*" <O ( ) ( ) j V y a x y a b a= ≤ + = − ! "=.P*".aX5FI0M"].4"56I6 b a− ! k k k k d <*+ ' ( ) ( ) x m x m x+ ≥ + + − + ( )( ) ( ) ( )x x x m x x x⇔ + − + ≥ − + + + 5€K45F x ≥ − "5,+E].C">N9.:7".>N9,>N92M5 x x m x x x x + + ≥ + − + − + ⇔ x x m x x x x + + − ≥ − + − + (z) _..6 x x x + − + HE].C">N9.:7"(z)*+XB9.•. m≥ () <*+ ‚ H ‚ ' ( ) x x t t x x x x x x − − + = = ⇔ = − + + − + − + ! I19E5J."5\ k O i '− + +∞ .y g i . ' ' ' + dQL ƒ ' G ' t + ∈ !I].C">N9.:7",{*"*+9"5F$4"52#*"e4"5()*+9"5F$ ƒ ' G ' t + ∈ 4"52#*"e4"5 ƒ ' „G … ' <O ( ) t M f t m + ∈ ≥ 2M5|(.)6.•. |y(.)6•. I19E5J."5\ . ' ' ' + |y(.) g i |(.) h •E19E5J."5\ ƒ ' „G … ' <O ( ) h t M f t khi x + ∈ = = dQLL*E..>N9,>N92M5 h m ≤ k k k d< ' >?9."@9,5SK<('G)*+XB9 <O ' by a b∆ + − − = >?9."@9 ∆ .B2M5"<5,>?9."@9 #d v d $W..<$95**D*+,e"0#95<*;< #d v d 4"52#*"e4"5 ( H ) ( H )d d∆ = ∆ %( HX ) %( HX )c c⇔ ∆ = ∆ k( ) k( ) a b a b a b a b a b a b − + ⇔ = + + ⇔ − = + a b a b ⇔ − = + "_* a b a b − = − − ' a b⇔ − = "_* ' a b+ = "c<6'HE6"_*<6HE6i'! dQL*+"<5,>?9."@9."s<${L\K*`KE#5.'OgL•62#O•'L6 k k k k do*.N*"eC">N9*;< x y z− + − ∆ = = − 2# ' x y z+ − − ∆ = = − 0`0>~.0# (G G)H ( GG)u v= − = − r r !_.C"@9()%9%92M5 ∆ 2# ∆ "Q*_C2o*.N k (G G)H ( GG)u v= − = − r r 0#$*_C2o*.N*"eC">N9! <*+ ( ) G G 'G jG '(GG) n − − = = − − = − ÷ − − r !_.C"@9()*+XB9 ()OgLg$6! _.*`K( )*+.D$(iGGi')2#E4P"U6'! _.C"@9().5JCOl*2M5( )4"52#*"e4"5 ( H( )) ' ' k m d I P R m − + + = ⇔ = ⇔ = ± + + dQL*+"<5$_.C"@9."s<${L\K*`K0#OgLg ' k 62#OgL• ' k 6! k k k ' <*+ ( ) ( ) ( ) h n h h h h ( ) ( ) ( ) ( ) i i i i i i i − = − − = − − = − = − dQLC"`."m**;<%&C"a*.:\0# h k k k k dE ' *,>?9.5F$*Q*;<()*+XB9 b y x a = ± !c5(O GL ) ( ) x y H a b ∈ ⇒ − = () *,>?9."@9X GX *+C">N9.:7"0# # b b b b y x y x v y x y x a a a a = + − = − + + *95<,5=$*;<X GX 2M5**,>?9.5F$*Q( G x y a b y x b a + + )HI( G x y a b y x b a − − )! x5F.P*""7"E7""#" 6 I 6!I!%5 AOB ∠ 6 ! ( ! )OA OB OAOB− uuur uuur uuur uuur <*+ !OA OB uuur uuur 6 (( ) ( ) )(( ) ( ) ) x y x y a b a b y x y x b a b a + + + − + − 6 ( ) h x y a b a b + − ÷ 6 h a b + ÷ (."o()) ( ! )OA OB uuur uuur 6 (( )( ) ( )( )) x x y y a a b b y y x x b b a a + − + + − 6 ( ) h x y a b a b − − ÷ 6 h a b − ÷ (."o()) x,+ ab S = 4"9,r5! k k k k c<,W.:c9.D$.<$95*I0#(GG) <*+ k k ( ) ( ) ( ) I ' ( ) ' MG GA MG GB MG GC MG GA GB GC MG GA GB GC MG GA GB GC GA GB GC + + = + + + + + = + + + + + + = + + + ≥ + + uuuur uuur uuuur uuur uuuur uuur uuuur uuur uuur uuur dQL gI g ≥ GA GB GC+ + X]KEq9O1L:<4"52#*"e4"5 M G ≡ k k ' <*+ ( ) h j h Hk j Hk h Hk j h 09 09 h09 h 09 09 h09 09 h09 h 09 h 09 09 09 09 09 j }09 09 x x x x x x x x x x x x x x x x x − ≥ + ≤ − ⇔ + ≥ + ≤ − − ≥ + ≥ ⇔ + ≤ − + > } k } 09 k 09 h x x x x x ≤ ≤ ⇔ ≤ − > ≤ ≤ ⇔ < ≤ QC9"5F$*;<E].C">N9.:7"0# 6 } k „G … (G … h ∪ k k k k . :94"995<*""<5,5=$HI*&,/"H,WX#5,BI6<Y!O 2# IL0#"<5Z< ,>?9."@92K99+*2M5"<K 2# *[92K99+*2M5I!:O 2# IL0]L"<5,5=$ 2# %< *"6E(2M5E0#$W.%&*".:>M* 2# EY<)! <). + *A.,-."/( $ ).B5',5=$C"DE5F.(G)HIH %<*"**.5JC.KLJ*;<( $ ).B5I 2# 2K99+*2M5"<K! Câu II (2 đim)! 1. 515"FC">N9.:7" ' ' ' ' x y y x + − = + − = 2. 515C">N9.:7" . :94"995<*""<5,5=$HI*&,/"H,WX#5,BI6<Y!O 2# IL0#"<5Z< ,>?9."@92K99+*2M5"<K 2# *[92K99+*2M5I!:O 2# IL0]L"<5,5=$ 2# %< *"6E(2M5E0#$W.%&*".:>M* 2# EY<)! <) ^*,/".D$ 2# E4P"$_.*`K9B5.5JC.aX5FI! E) ^*,/" 2/ .:P*;< 2# %<*".aX5FI*+."=.P*"0M"].! Câu