15 de kt1t mu logarit

www.MATHVN.com Toỏn hc Vit Nam www.MATHVN.com KIM TRA TIT CHNG S 13 MễN: GII TCH 12 Thi gian lm bi: 45 phỳt H v tờn thớ sinh: Lp Cõu 1: Tp xỏc nh ca hm s y = A [ 1; 4] C ( 1;4 ) x x l: B ( ; 1] [ 4; + ) D ( ; 1) ( 4; + ) B x = Cõu 3: Rỳt gn A = a a A + a C x = 11 + a2 B a ( C + a Cõu 4: o hm ca hm s y = log3 x + 3x C y ' = 2x + x + 3x ( x + 3) ln + = cú nghim l: log x + log x B ; 10 10 A {10; 100} ( Cõu 6: Cho hm s y = x ) C y ' = x (x ) 3 8) D Khi ú: C {1; 20} ma th ( 2x + ( x + 3x 2) ln D y ' = ( x + 3) ln x2 + 3x A y ' = x l: B y ' = Cõu 5: Phng trỡnh ) D + a A y ' = D x = co A x = m Cõu 2: Phng trỡnh log ( x 3) + log ( x 1) = cú nghim l: B y ' = D y ' = ( x3 ) ( 3x ) 1 Cõu 7: Nu log = a thỡ log 9000 bng: A + 2a ( ) B a + C a D 3a Cõu 8: Cho y = ln x + Khi ú y ' (1) cú giỏ tr l: A B C D 125 theo a: B ( a + 5) C (1 + a ) D + 7a Cõu 9: Cho log = a Tớnh log A 5a Cõu 10: S nghim ca phng trỡnh x 3.2 x + = l: A B C Cõu 11: Cho > Kt lun no sau õy ỳng ? Facebook.com/mathvncom 26 D www.MATHVN.com Toỏn hc Vit Nam A < B . = ( Cõu 12: Cho hm s y = x + x ) C + = Khi ú: A y ' = ( x + 1) ( B y ' = x + x Cõu 14: Giỏ tr ca a A C C 49 B Cõu 15: Tp xỏc nh ca hm s y = x A D = [ 2;1] + x B D = R l: C D = ( 2;1) ) D D = R \ {1; 2} D 5log b a Cõu 17: Hm s y = log x x cú xỏc nh l: B D = [ 0;5] A ( ;0 ) ( 5; + ) ( x + 1) D Cõu 16: Giỏ tr ca biu thc C = log a l: b A 5log b a B 5log a b C 5log a b ( + x 4) D 10 ( < a 1) l: 22+ 51+ B 10 a ) ln ( x D y ' = ( x + x ) 102+ log co A m C y ' = ( x + x ) Cõu 13: Rỳt gn A = D > C ( ;0] [5; + ) D D = ( 0;5 ) Cõu 18: Cho x1 , x2 l hai nghim ca phng trỡnh 5x + 53 x = 26 Khi ú tng x1 + x2 cú giỏ tr: A B C D ( < a 1) l: ma th Cõu 19: Giỏ tr ca log a a A B Cõu 19: Biu thc A x B x Cõu 20: Giỏ tr ca a log a2 5 ( < a 1) D Cõu 21: Hm s y = ( x 1) C x D x l: B 52 A R\ {1} x x x5 (x > 0) vit di dng lu tha vi s m hu t : A 58 C C 54 D cú xỏc nh l: B ( ;1) D (1;+ ) C R Cõu 22: o hm ca hm s y = 2016 x l: A y ' = 2016 x B y ' = x 2016 x 2016 x C y ' = 2016 ln 2016 D y ' = ln 2016 x Cõu 23: Hm s y = x.e x cú o hm bng: A y ' = x e x B y ' = e x Facebook.com/mathvncom C y ' = xe x 27 D y ' = e x + xe x www.MATHVN.com Toỏn hc Vit Nam x2 + x + = Khi ú tớch x1.x2 cú giỏ tr: D Cõu 25: Cho log = a; log = b Tớnh log 2016 theo a v b: A + 2a + 3b B + 2a + b C + 3a + 2b D + 3a + 2b Cõu 26: Tỡm mnh ỳng? Cõu 24: Cho x1 , x2 l hai nghim ca phng trỡnh A B C y= ( 3) C Hm s y = x luụn nghch bin x D Hm s y = luụn nghch bin luụn nghch bin m A Hm s x y= luụn ng bin B Hm s x Cõu 27: Cho phng trỡnh log 22 x + 5log 3.log x = Tp nghim ca phng trỡnh l: ;1 64 ; 64 B C Cõu 28: Hm s y = x cú xỏc nh l: B ( ;0 ) A C ( 0; + ) Cõu 29: Phng trỡnh log x + 3log x = cú nghim l: A {4; 16} B {2; 8} ( A B C ) ( < a 1) C ma th - HT Facebook.com/mathvncom D \ {0} D {4; 3} l: Cõu 30: Giỏ tr ca log log a a D {1;2} co A 28 D www.MATHVN.com Toỏn hc Vit Nam www.MATHVN.com KIM TRA TIT CHNG S 14 MễN: GII TCH 12 Thi gian lm bi: 45 phỳt H v tờn thớ sinh: Lp Cõu 1: Tỡm m phng trỡnh log 22 x log x + = m cú nghim x [1; 8] A m B m C m D m B a 2b14 C a 8b14 Cõu 3: Nghim ca phng trỡnh: A B D a 4b x = 0,125.42x l: C D co A a 6b12 m Cõu 2: Nu log x = log ab log a 3b (a, b > 0) thỡ x bng: 3 31 Cõu 4: Tớnh: = : 42 + ( 32 ) : 53.252 + ( 0, ) ta c 33 A B C 3 13 D Cõu 5: Tỡm m phng trỡnh log 32 x ( m + 2).log x + 3m = cú nghim x1, x2 cho x1.x2 = 27 B m = 28 Cõu 6: Nghim ca bt phng trỡnh log 22 x log A x > 1 A R\ ; 2 B (0; +)) Cõu 8: Hm s f(x) = x ln x t cc tr ti im: A x = B x = e e Cõu 9: Hm s y = ln A (-2; 2) ( x + l: D 0; [ 4; + ) cú xỏc nh l: ma th D m = 25 C < x B x Cõu 7: Hm s y = ( x 1) C m = A m = C R 1 D ; 2 C x = e D x = e ) x + x x cú xỏc nh l: B (- ; -2) (2; +) C (- ; -2) D (1; + ) 1 y y Cõu 10: Cho = x y + Biu thc rỳt gn ca l: x x A x B 2x C x + D x x x Cõu 11: Tỡm m phng trỡnh - 2(m - 1).2 + 3m - = cú nghim x1, x2 cho x1 + x2 = A m = B m = C m = Cõu 12: Nghim ca phng trỡnh log 22 x + 3log 2x = l: A ẳ B -1 v -2 C ẳ v ẵ Facebook.com/mathvncom 29 D m = D -2 www.MATHVN.com Toỏn hc Vit Nam Cõu 13: Nghim ca phng trỡnh log ( B v A 5.2 x ) = x l: 2x + D C Cõu 14: S nghim ca phng trỡnh 6.9 x 13.6 x + 6.4 x = l: A B C D x 5+3 +3 cú giỏ tr bng: 3x x C D 2 x Cõu 15: Cho x + x = 23 Khi o biu thc = B m A Cõu 16: Nghim ca phng trỡnh log ( x 1) + log (2x 1) = l: co A Vụ nghim B C D Cõu 17: Cho a > v a 1, x v y l hai s dng Tỡm mnh ỳng cỏc mnh sau: x log a x A log a = B log a ( x + y ) = log a x + log a y y log a y 1 C log a = D log b x = log b a.log a x x log a x Cõu 18: Hm s y = x x + cú o hm f(0) l: 1 A B C 3 Cõu 19: Giỏ tr nh nht ca hm s f ( x) = x(2 ln x) trờn [2 ; 3] l: A B e C 4-2ln2 Cõu 20: Gii phng trỡnh log ( x ) log 2 A x = v x = - ( 2+ ) +( C x = v x = ma th Cõu 21: Gii phng trỡnh {- 4, 4} {2, D -2 + 2ln2 ( x ) = Ta cú nghim B x = v x = x D ) } x D x = v x = = Ta cú nghim bng : C {-2, 2} D {1, - 1} Cõu 22: Nghim ca bt phng trỡnh log (4x 3) + log (2x + 3) l: A x 3 B x> Cõu 23: S nghim ca phng trỡnh 3x.2 x = l: A B C < x D Vụ nghim C D 2 Cõu 24: Nghim ca bt phng trỡnh A x B x Cõu 25: Biu thc x 36.3 x + l: C x D x x x x5 (x > 0) vit di dng lu tha vi s m hu t l: 5 A x B x C x D x Facebook.com/mathvncom 30 www.MATHVN.com Toỏn hc Vit Nam www.MATHVN.com KIM TRA TIT CHNG S 15 MễN: GII TCH 12 Thi gian lm bi: 45 phỳt H v tờn thớ sinh: Lp log a l: A B 25 Cõu 2: S nghim ca phng trỡnh A C x2 + x2 = D B m Cõu 1: Giỏ tr ca a C D co Cõu 3: Tỡm mnh ỳng cỏc mnh sau: A Hm s y = a x vi < a < l mt hm s ng bin trờn (-: +) B Hm s y = a x vi a > l mt hm s nghch bin trờn (-: +) x C th hm s y = a v y = (0 < a 1) thỡ i xng vi qua trc tung a D th hm s y = a x (0 < a 1) luụn i qua im (a ; 1) x Cõu 4: Phng trỡnh 31+ x + 31 x = 10 Chn phỏt biu ỳng? A Cú hai nghim dng B Vụ nghim C Cú hai nghim õm D Cú mt nghim õm v mt nghim dng Cõu 5: Hm s no di õy l hm s ly tha: A y = x ( x > 0) C y = x ( x 0) B y = x D C cõu A,B,C u ỳng ma th Cõu 6: Giỏ tr ca log a a a a a l: A 13 10 B C Cõu 7: Cho log 27 = a; log = b; log = c Tớnh log12 35 bng: 3b + 3ac 3b + 2ac 3b + 2ac A B C c+2 c+2 c+3 D D 3b + 3ac c +1 H thc liờn h gia y v y khụng ph thuc vo x l: 1+ x A y ' y = B yy ' = C y '+ e y = D y ' 4e y = Cõu 8: Cho y = ln ( Cõu 9: Hm s y = log x x ) cú xỏc nh l: B (0; 4) A Cõu 10: Tng cỏc nghim ca phng trỡnh A B log C (2; 6) x C 19 x2 D (0; +) + = l: D Cõu 11: Giỏ tr ca a a l: A 198 B 1916 C 192 D 194 Cõu 12: Trong cỏc hm s sau, hm s no ng bin trờn khong (0;+ ) : Facebook.com/mathvncom 31 www.MATHVN.com Toỏn hc Vit Nam A y = log B y = log a x, a = x C y = log x D y = log x Cõu 13: Tp nghim ca phng trỡnh log (3 x ) log 2x = l: { } { } B 31 ( { } Cõu 14: Hm s y = log x x + C ) D cú o hm l : A y ' = ( x 1) ln C y ' = B y ' = ( x 1) ln x2 x + 2x D y ' = ( x x + 5) ln 2x x2 x + m A 32 13 a a + a cú giỏ tr l: Cõu 15: Cho a, b l cỏc s dng Khi ú, A = a4 a4 + a A a B 2a C 3a D 4a x +1 x +1 Cõu 16: Tp nghim ca phng trỡnh 6.2 + = l: A { 2;3} co B {0;1} C {0;3} D {1;2} x x Cõu 17: Tớch s cỏc nghim ca phng trỡnh + 35 + 35 = 12 l: A B C D Cõu 18: S nghim ca phng trỡnh log (2 x 1) = l: A B C Cõu 19: Tp nghim ca phng trỡnh log x + log x + log16 x = l: { 2} { } y = ( x x + 2) e B 2 ma th A Cõu 20: Hm s A y ' = x e x + Cõu 21: Bin i A x x C {4} D D {16} cú o hm l: B y ' = xe x C y ' = ( x ) e x D y ' = x e x x x , ( x > 0) thnh dng ly tha vi s m hu t ta c: 20 B x 23 12 C x 21 12 D x 12 Cõu 22: o hm ca hm s y = x l: A x B 33 x Cõu 23: Nu log = a thỡ log 4000 bng: A + a B + a Cõu 24: Hm s y = A ln x x2 ln x cú o hm l: + x x ln x B x Facebook.com/mathvncom C 23 x D x2 C + 2a D + 2a C Kt qu khỏc D 32 ln x x www.MATHVN.com Toỏn hc Vit Nam ma th co m b b 12 Cõu 25: Cho a, b l cỏc s dng Khi ú, B = + : a b cú giỏ tr l: a a 3a A a B C 2a D a Facebook.com/mathvncom 33 www.MATHVN.com - Toỏn hc Vit Nam 1: Cõu Tp xỏc nh ca hm s y x l: A ;1 D R \ C R \ B R Cõu 2: Hm s y ( x2 x 3) cú xỏc nh l: A 3;1 B (; 3) (1; ) C R \ 3;1 D ( 3;1) a2 a2 a4 a 0, a l: 15 a 12 B C 5 A om Cõu 3: Giỏ tr ca biu thc log a D thv n.c 3 2 Cõu 4: Tớnh M : : 25 0, ta c 33 A B C D 3 13 Cõu 5: Tp xỏc nh ca hm s y log3 (2 x 1) l: 1 1 A D (; ) B D (; ) C D ( ; ) D D ( ; ) 2 2 x Cõu 6: Tp xỏc nh ca hm s y log l: x2 B ;1 A ;1 2; D 2; C 1; Cõu 7: o hm ca hm s y ( x x 3) l: A x 2x B x x 2x Cõu 8: o hm ca hm s y (1 x ) x B x x 2x C (1 x ) 2 Cõu 9: Cho f ( x) ln( x 1) o hm f '(1) bng: A B C Cõu 10: Cho f ( x) ln sin x o hm f '( ) bng: A Cõu 11: Biu thc D x x 2x l: x ma A x C D 2x (1 x ) D B C D x x x5 (x > 0) vit di dng lu tha vi s m hu t l: A x B x C x D x Cõu 12: Bit a log12 27 Tớnh theo a biu thc log 16 cú giỏ tr l: A 4(3 a ) a B 4(3 a ) a Facebook.com/mathvncom C a a D a a www.MATHVN.com - Toỏn hc Vit Nam Cõu 13: Cho > Kt lun no sau õy l ỳng? A < B > C + = Cõu 14: Hm s no di õy ng bin trờn xỏc nh ca nú? x x B y = C y = Cõu 15: Cho x x 23 Khi ú biu thc M A B Cõu 16 Tp nghim ca phng trỡnh 22 x A S 1;5 ; B S 1; ; 2 x B S 3; x D y = 3x x cú giỏ tr bng: 3x x C D 2 l C S ;1 ; Cõu 17: Tp nghim ca phng trỡnh ( 10 3) A S 3; e x om A y = 0,5 D . = x x ( 10 3) x x C S 7; D S l: D S thv n.c Cõu 18 Tp nghim ca phng trỡnh log x log3 x log x.log3 x l A S 1;6 ; B S 1;3 ; C S 2;log3 ; D S 2;log2 Cõu 19 Bit a log 28 98 Tớnh theo a biu thc log 49 14 cú giỏ tr l: A a 2a B a 2(2a 1) C a 2(2a 1) a 2a D Cõu 20 Tp nghim ca bt phng trỡnh 22 x 22 x 22 x 27 x 25 x 23 x l 10 10 ; D x 3 Cõu 21 Tp nghim ca bt phng trỡnh log ( x 7) log ( x 1) l A x ; A 1;2 B x ; C x B (2; ) C 3; D ( 7; 1) 21 log l: 10 100 A x ; B x ; C x ; D x 9 3x l: Cõu 23 Tp nghim ca bt phng trỡnh log x ma Cõu 22 Tỡm x bit log x log A (; 2) ; B ; ; C ; D ; Cõu 24: Tỡm m phng trỡnh log x log x m cú nghim x [1;8] A m B m C m D m x x Cõu 25: Gớa tr no ca m thỡ phng trỡnh 10.3 m cú nghim phõn bit A m 25 B 25 m C m D ỏp ỏn khỏc 2 2: Facebook.com/mathvncom www.MATHVN.com - Toỏn hc Vit Nam A C log B 125 D log x x Cõu 24: Gớa tr no ca m thỡ phng trỡnh 15 m 15 cú hai nghim phõn bit? B m 16 C m 1 Cõu 25: Gớa tr no ca m thỡ phng trỡnh B m A m x D m 4m cú mt nghim nht? D m C m 6: Cõu Tp xỏc nh ca hm s y (4 3x x )e l: A (2;2) B R C (; 2) (2; ) Cõu Tp xỏc nh ca hm s y ln( x 9) l: a Rỳt gn biu thc I D C 3;3 B (; e] [e; ) A (; 3) (3; ) om A m D (2; ) thv n.c (vi x ) ta c: a 1.a A I a ; B I a2 ; C I a3 ; D I a4 Cõu 4: Cho hm s y 2e x sin x Biu thc y y ' y '' c rỳt gn li l : A y B y C 3y D y Cõu Cõu 5: Cho f ( x) tan x v ( x) ln( x 1) Giỏ tr biu thc A B f '(0) l: '(0) C 10 x l : x 3x B ;10 C (;1) (2;10) Cõu 6: Tp xỏc nh ca hm s y log D 2 A (1; ) D (2;10) Cõu 7: Bit x log 6; y log Tớnh theo x; y biu thc log 217818720 cú giỏ tr l: A x y B x y C x y D x y ma Cõu 8: Tớnh giỏ tr ca biu thc P a log a log 2017 ta c: 1 ; C P ; D P 2 x x x x Cõu 9: Cho 23 Khi ú biu thc M cú giỏ tr bng: A B C 2 D B P A P ; Cõu 10: Biu thc A x y 4 4 M ( x y )( x y )( x y ) c rỳt gn li l: Cõu 11: Cho f ( x) 1 B x 32 y 32 2x o hm cp hai f ''(0) bng: ex Facebook.com/mathvncom C x16 y 16 11 D x y www.MATHVN.com - Toỏn hc Vit Nam A (2ln 1)2 B ln e2 C ln e2 D Cõu 12: Cho a Tỡm mnh sai cỏc mnh sau: om A log a x x B log a x x C Nu x1 x2 thỡ log a x1 log a x2 D th hm s y log a x cú tim cn ngang l truc honh Cõu 13: Trong cỏc khng nh sau õy, khng nh no l khng nh ỳng: A log B log log C log D log ( 1) Cõu 14: Tng cỏc nghim ca phng trỡnh 2(log9 x) log3 x.log3 ( x 1) l: A B C D Cõu 15: Tp nghim ca phng trỡnh lg ( x 1) 2lg ( x 1) 40 l: A 10 ;10 D 10 2; thv n.c Cõu 16 Phng trỡnh: 342 x 953 x x C 10 1;10 B 10 1;10 1 10 B.Cú mt nghim thuc khong (1; 2) A.Cú hai nghiờm trỏi du C.Cú ớt nht mt nghim thuc khong (1; 4) Cõu 17: Phng trỡnh: x x 2 x 2 D.Cú hai nghiờm õm 32 x1 B Cú mt nghim x log A Cú hai nghiờm dng C Cú ớt nht mt nghim thuc khong (1;0) D Vụ nghiờm Cõu 18 Phng trỡnh sau log (3.2 x 8) x cú nghim l x1 ; x2 thỡ tng x1 x2 l: A B 12 C D log2 Cõu 19 Phng trỡnh sau log x log 25 x log 0,2 cú nghim l: C S D S 3; 3 x x x Cõu 20 Phng trỡnh sau 3.16 2.81 5.36 cú nghim l: A S 1, B S 0;1 C S 0; D S ; 2 Cõu 21 Phng trỡnh sau log x 3log x log x cú nghim l: B S 3; ma A S 3 ; 16 A S B S ; Cõu 22.Tp nghim ca bt phng trỡnh Facebook.com/mathvncom C S ; 12 x x 12 l D S ; www.MATHVN.com - Toỏn hc Vit Nam x ; x B ( 4; 3) A x C (3; 4) D x Cõu 23: Gớa tr no ca m thỡ phng trỡnh x 8.2 x m cú nghim A m B m 16 C m 16 D m Cõu 24 Tp nghim ca phng trỡnh 533 x 5x x 51 x x l: 13 ; 2 13 C S ; ; 2 A S B S 13 ; ;0 om 13 13 ; D S ; ; 2 Cõu 25: Gớa tr no ca m thỡ phng trỡnh x 2m cú mt nghim nht? 5 A m B m C m D m 2 thv n.c 7: Cõu Tp xỏc nh ca hm s y (4 3x x )5 l: A (1; 4) B R C (; 4) (1; ) Cõu Tp xỏc nh ca hm s y ln( x x 10) l: Cõu Biu thc M A C 2;5 B (; 2) (5; ) A (;5) 57 72 B 53 54 4 4 D D (2; ) vit i dng ly tha vi s m hu t l: 19 36 C 48 D 37 72 Cõu 4: o hm ca hm s y x l: A (1 x ) B x x C x D x (1 x )3 ma Cõu 5: o hm ca hm s y x x x x l : A 2x C B x 15 1616 x Cõu 6: o hm ca hm s f x ecos2x ti x D 15 16 16 x15 l: A 3e B 3e C 3e D 3e Cõu 7: Bit a log 2; b log Tớnh theo a, b biu thc log1399680 cú giỏ tr l: A 6a 7b B 6a 6b Cõu 8: Tớnh giỏ tr ca biu thc K 81 1 log9 4 Facebook.com/mathvncom C 7a 6b D 7a 7b 25log125 49log7 ta c: 13 www.MATHVN.com - Toỏn hc Vit Nam B P A P 20 ; ; Cõu 9: Kt qu rỳt gn biu thc a a 2 A a (a > 0), l B 2a Cõu 10: Biu thc 9a 16a 1 2 C 3a a 12a D P C P 19 ; D 4a c rỳt gn li l: A 2e B 10 e2 C e om 3a 4a a 3a A a B a C 4a D 3a x Cõu 11: Giỏ tr ln nht ca hm s y f ( x) ( x x 2)e trờn on 1;2 l: D e thv n.c Cõu 12: Tỡm mnh ỳng cỏc mnh sau: A Hm s y 2x ng bin khong (0; ) B Hm s y 2x nghch bin khong (0; ) C Hm s y 2x nghch bin khong (; ) D Hm s y 2x ng bin khong (; ) Cõu 13: Trong cỏc khng nh sau õy, khng nh no l khng nh sai: A log B log log 11 C log D log ( 1) Cõu 14: Tng cỏc nghim ca phng trỡnh log x 2log7 x log x.log x l: A 10 B 11 C 12 D ỏp s khỏc Cõu 15: Nghim x0 ca phng trỡnh log2 (1 x ) log7 x nm khong no sau õy? A x0 B 20 x0 50 C 100 x0 200 D 300 x0 400 Cõu 16 Cho a log Khi ú log 9000 tớnh theo a l: ma A 2a B a C 3a D 9a Cõu 17: Tp nghim ca phng trỡnh 31 x 31 x 10 l: A Hai nghim trỏi du B Hai nghim dng C Hai nghim õm D Vụ nghim x x1 Cõu 18 Tng cỏc nghim ca phng trỡnh 25 6.5 l: A B C D x x Cõu 19 Phng trỡnh sau 7.2 12 cú nghim l: A S 3;4 B S 3; C S log2 3; log2 D S log2 3;log2 x Cõu 20 Tp nghim ca bt phng trỡnh l A x ; B x ; C x ; D x Cõu 21 Phng trỡnh sau log 2 x 3log x log x cú nghim l: 2 A S ; B S ; C S ; D S ; Cõu 22 T s gia nghim ln v nghim nh hn ca phng trỡnh log x log x l: Facebook.com/mathvncom 14 A 10 www.MATHVN.com - Toỏn hc Vit Nam B 103 C 10 D 105 Cõu 23 Tỡm tt c cỏc giỏ tr thc ca tham s m phng trỡnh 2log52 x log5 x m cú B m nghim : A m 1 C m D m Cõu 24: Tp nghim ca phng trỡnh log22 x log32 x 2log3 x l : log 2 B 3log ;3 A log 2;log 2 D log 2;log C log 6;log 2 om Cõu 25: Tp nghim ca phng trỡnh 2log3 (cot x) log cos x l : A m2 ; m Z B m2 ; m Z C m2 ; m Z D m2 ; m Z 8: Cõu Tp xỏc nh ca hm s y (5 x x2 )2017 l: A (1; 4) B R C (; 4) (1; ) Cõu Tp xỏc nh ca hm s y log( x 16 x 60) l: D thv n.c A (;10) B (;6) (10; ) C 6;10 D (6; ) Cõu Giỏ tr ca biu thc log4 l 3 B C D 2 Cõu 4: Cho hm s y ln x Biu thc x y '' x y ' c rỳt gn li l : A A B.1 C D Cõu 5: Hm s f ( x) x ln( x 1) cú o hm f '(1) l: A ln B ln C ln D ln x Cõu 6: Cho f ( x) e o hm cp hai f ''(1) bng: A 6e B 9e C 15e D 9e3 Cõu 7: Bit a log 2; b log Tớnh theo a, b biu thc log 38880 cú giỏ tr l: A 4a 4b B 5a 4b C 5a 5b D 4a 5b ma Cõu 8: Biu thc log a (log a N )3 c rỳt gn li l: log a (log a N ) B C D 1 Cõu 9: Cho N 2017! Giỏ tr ca biu thc P l: log 2017 N log N log N A A P 2017!; B P 2016! ; C P 2017 ; D P Cõu 10: Biu thc (log a b logb a 2)(log a b log ab b) logb a log a b c rỳt gn li l: B C D Cõu 11: Bit a log 20 3; b log 20 5; c log 20 Theo a; b; c biu thc log 20 44100 cú giỏ tr l: A A 2a b 2c B a 2b 2c Cõu 12: Khng nh no sau l sai ? C 2a 2b c Facebook.com/mathvncom 15 D a b c www.MATHVN.com - Toỏn hc Vit Nam A log3 B log x 2016 log x2 2017 C log log D log 0,3 2016 2017 C th hm s y x luụn i qua im 2; x om Cõu 13: Cho ba s a log15 14; b log7 8; c log6 37 Bt ng thc no sau õy ỳng ? A a b c B a c b C c b a D b a c Cõu 14: Mnh no sau õy sai ? A Hm s y x l hm s ng bin trờn ; B x lim x D th hm s y x v y i xng qua truc tung Cõu 15: Tng cỏc nghim ca phng trỡnh x x x l: A B C D x x x x2 Cõu 16 Phng trỡnh: A Cú hai nghiờm dng B Cú mt nghim thuc khong ( 2; 2) C Cú ớt nht mt nghim thuc khong (1; 4) D Cú mt nghim õm x x Cõu 17: Tp nghim ca phng trỡnh 17 l: A Hai nghim trỏi du B Hai nghim dng C Hai nghim õm D Vụ nghim 2 Cõu 18 S nghim ca phng trỡnh ln( x x 3) x ln( x x 3) l: A B C D thv n.c x Cõu 19 Tp nghim ca phng trỡnh ( 2) ( 2) ( 4) x A S 3; x2 B S 3;1;0 C S 3; ;1 x 2x l: D S 2; ;3 Cõu 20 Tp nghim ca phng trỡnh log a x log x log a x.log x (a 0; a 1) l: A 2;a B 2a;1 C a;1 D a; Cõu 21 Biu thc B log6 30 C log30 ma A log15 49 log 7.log log 7.log log 7.log c rỳt gn li l: log 7.log 7.log Cõu 22 Biu thc M D log7 30 1 vi 10 thỡ M cú giỏ tr : log log B M C M D M A M Cõu 23 Tp nghim ca bt phng trỡnh 64.9 x 84.12 x 27.16 x l A (1; 2) B (;1) (2; ) 4 C ( ; ) D vụ nghim Cõu 24: Gớa tr no ca m thỡ phng trỡnh log2 ( x2 x 5) m log x x5 cú hai nghim phõn bit: A 25 m0 B 25 m C m Cõu 25: Tng cỏc nghim ca phng trỡnh x Facebook.com/mathvncom x x1 16 25 36 l : D m www.MATHVN.com - Toỏn hc Vit Nam A log B log 2 C log 9: Cõu Cho hàm số y x x Đạo hàm là: A [0; 2] D log 5 f '( x ) ca hm s ó cho có tập xác định C (;0) (2; ) B (0; 2) D (;0]) [(2; ) Cõu Tp xỏc nh ca hm s y log( x 15 x 50) l: B (;5) (10; ) A [5;10] Cõu Nu log ab A C 5;10 a5 a thỡ log a 3b bng: b B C C y ' 2x x 3x 2 D (;5] [10; ) D thv n.c Cõu 4: o hm ca hm s y log3 x 3x l: A y ' om B y ' x ln 2x x 3x ln D y ' x ln x 3x Cõu 5: o hm hm s y x x l: A x B x x ln x x 3 ma 4 1 C x x D x x x 4 Cõu 6: Cho log a Khi ú log3 18 tớnh theo a l: a 3a A B C 3a D 3a a a Cõu 7: o hm ca hm s y (2 x 3).2 x ti x l: A 5ln B 3ln C 3e ln D 2ln Cõu 8: Bit a log 5; b log Tớnh theo a, b biu thc log1458000000 cú giỏ tr l: A 5a 5b B 5a 6b C 6a 6b D 6a 5b a a3 a Cõu 9: Tớnh giỏ tr ca biu thc P log ta c: a a a a 23 31 A P ; B P ; C P ; D P 15 60 Facebook.com/mathvncom 17 www.MATHVN.com - Toỏn hc Vit Nam 4 a a Cõu 10: Biu thc a a A a b A b b b 2 c rỳt gn li l: B a b C a b D ỏp ỏn khỏc 216 v a thỡ x bng: B a b C a a D a2 om Cõu 11: Nu x thv n.c Cõu 12: Giỏ tr ca biu thc M log a vi (a 0; a 1; b 0) l: b 7 A B 7log a b C log a b D log b a log a b log a c log a b c rỳt gn li l: Cõu 13: Biu thc log ab c A B log a b C log a b D Cõu 14: Mnh no sau õy sai ? A Hm s y x l hm s ng bin trờn ; B x lim x C th hm s y x luụn i qua im 2; x D th hm s y x v y i xng qua truc tung Cõu 15: Tng cỏc nghim ca phng trỡnh x 5.2 x l: D log3 C log A Cú hai nghiờm dng B Cú mt nghim thuc khong ( 2; 2) C Cú ớt nht mt nghim thuc khong (1; 4) D Cú mt nghim õm ma A B 2,58 Cõu 16 Phng trỡnh: x 3x 3x x Cõu 17: Tp nghim ca phng trỡnh 51 x 51 x 26 l: A Hai nghim trỏi du 2 B Hai nghim dng C Hai nghim õm D Vụ nghim Cõu 18 Hm s no di õy ng bin trờn xỏc nh ca nú? A y = 0,5 x B y = x C y = x e D y = x Cõu 19 Tp nghim ca phng trỡnh log a x log3 x log a x.log3 x (a 0; a 1) l: Facebook.com/mathvncom 18 www.MATHVN.com - Toỏn hc Vit Nam A 3; a Cõu 20 Biu thc a a D 2a;1 C 2a;1 B 3a;1 a c rỳt gn li l: ; C.1 ; a Cõu 21 Hm s no cú th nh hỡnh ve di õy? B D A y x thv n.c om A a ; B y D y C y x x Cõu 22 Cho log a x 2; logb x 3; logc x ú giỏ tr ca biu thc log abc x bng : A 36 B C D x x x Cõu 23 Tp nghim ca bt phng trỡnh 6.9 13.6 6.4 l A ( 1;1) 3 B (; 1) (1; ) D vụ nghim C ( ; ) Cõu 24: Hm s y log ( x 2mx 9) cú xỏc nh l R ; nu: A m (; 3) (3; ) B m (3;3) C m [3;3] D m Cõu 25: Tp nghim ca phng trỡnh 3x.2x l: ma 1 B 0; log3 A ; C 0; 1,58 D 0; log2 10: 12 Cõu Rỳt gn A a a a ta c kt qu l: A a C a B a D a2 Cõu o hm ca hm s y x ny l: A x ln B x Facebook.com/mathvncom C x x 19 D x www.MATHVN.com - Toỏn hc Vit Nam Cõu Bit a log x 27 Tớnh theo a biu thc log B A a 3a C x cú giỏ tr l: a D 3a Cõu 4: o hm ca hm s y ln x l: A B C D 15 ln 5x x ln x Cõu 5: o hm ca hm s y log (2 x 1) l: 2 ln A B C (2 x 1) ln (2 x 1) ln (2 x 1) D 72 x o hm cp hai f ''(0) bng: 2x ln ln A (2ln ln 2) B C 2ln ln e2 Cõu 7: Cho f ( x) x lg x o hm f '(10) bng: 2 A 10 B C ln10 ln10 Cõu 8: Tp xỏc nh ca hm s y log 2016 (4 x 12 x 9) 2017 l : 2 (2 x 1) ln x D ỏp ỏn khỏc D ln10 thv n.c Cõu 6: Cho f ( x) A ( ; ) x ln x om x ln x B 0; C (; ) \ 125 c tớnh theo a l: 5a 3a 3a A B C 2a 2a 2a e Cõu 10: o hm ca hm s y (4 x ) l: D (; ) Cõu 9: Cho log2 a Biu thc l og A e(4 x )e1 ln e e(4 x )e1 (4 x) B xe(4 x )e1 ln e D C x(4 x )e1 Cõu 11: Bit logb a b 0, b 1, a Tớnh biu thc P log 3 ma A Cõu 12: Bit log3 a A B a B 3a 2a a b C D a cú giỏ tr l: b Tớnh biu thc log a log3 a log a 2log3 a cú giỏ tr l: C D log a c log a b c rỳt gn li l: log ab c A B log a b C log a b x Cõu 14: Tng cỏc nghim ca phng trỡnh 8.2 x 15 l: A B 3,9 C log 15 Cõu 13: Biu thc Cõu 15 Bit x y 5xy; x, y Giỏ tr biu thc M Facebook.com/mathvncom D 20 D D log log x log y l: log ( x y ) www.MATHVN.com - Toỏn hc Vit Nam A B C D Cõu 16: Tp nghim ca bt phng trỡnh x x log3 x l: A 3; D 3; C 4; B ; Cõu 17: Mnh no sau õy sai ? A Hm s y ( ) x l hm s nghch bin trờn ; x om lim( ) x B x C th hm s y luụn i qua im 2; x x D th hm s y v y i xng qua truc honh Cõu 18 Tng cỏc nghim ca phng trỡnh 25x 7.5x 10 l: A log5 B C D log5 10 thv n.c Cõu 19 Hm s no di õy nghch bin trờn xỏc nh ca nú? A y x B y x C y D y e x x Cõu 20 Tp nghim ca phng trỡnh log a x log5 x log a x.log5 x (a 0; a 1) l: A 5; a B 5a;1 C a;1 D a;5 Cõu 21 Phng trỡnh sau log 2 x 3log x log x cú nghim l: A S ; ; 16 C S B S ; D S ; Cõu 22 Cho log a x 2; logb x 4; log c x ú giỏ tr ca biu thc log abc x bng : A B C D Cõu 23 Tp nghim ca bt phng trỡnh 6.9 x 13.6 x 6.4 x l B (; 1) (1; ) ma A ( 1;1) 3 C ( ; ) D vụ nghim Cõu 24: Hm s y log2 ( x2 2mx 4) cú xỏc nh l R ; nu: A m (; 2) (2; ) B m (2; 2) C m [2;2] Cõu 25: Tng cỏc nghim ca phng trỡnh x A log B log D m x 3x 1,5 l : C log D log3 11: Cõu Tp xỏc nh ca hm s y (2 x )3 l: A ( 2; 2) C (; 2) ( 2; ) B R Cõu Hm s y ( x2 x 3) cú xỏc nh l: Facebook.com/mathvncom 21 D R \ 2; www.MATHVN.com - Toỏn hc Vit Nam A 3;1 C R \ 3;1 B (; 3) (1; ) Cõu 3: Tp xỏc nh ca hm s y lg x2 x l: x B (3; ) A (0;1) (3; ) D ( 3;1) C (1;2) \ D (0;1) Cõu Tp xỏc nh ca hm s y log x x l: 3 A ; 1; ; B ; ; ; 2 Cõu 5: o hm ca hm s y log3 (2 x 1) l: (2 x 1) ln (2 x 1) ln B C om A D ;1 C 1; ; ln (2 x 1) D 22 x Cõu 6: Cho f ( x) x o hm cp hai f ''(0) bng: ln ln A (2ln ln 3)2 B C 2ln ln3 e2 Cõu 7: Cho f ( x) x log x o hm f '(10) bng: 10 10 A B 20 C 10ln10 ln10 ln10 (2 x 1) ln x thv n.c D ỏp ỏn khỏc D 20 10ln10 Cõu 8: Cho 16 x 16 x 62 Khi ú biu thc M 4x x cú giỏ tr bng: A B C Cõu 9: Biu thc A 2( a b) Cõu 10: Biu thc a3 a3 a3 a a3 a3 a C log b a (log a b log b a 1) log a b B log a b a D C a b D ỏp ỏn khỏc c rỳt gn li l: log a b D logb a log a b log b a Tớnh biu thc log a log3 a log a 2log3 a cú giỏ tr l: B C D Cõu 12: Giỏ tr ca biu thc P log3 2.log 3.log5 log31 30.log32 31 l: ; D.ỏp ỏn khỏc 32 Cõu 13: Tng cỏc nghim ca phng trỡnh 16 x 2.4 x1 12 l: A B 2, 29 C log 12 D log log x log y Cõu 14 Bit x y 5xy; x, y Giỏ tr biu thc M l: log ( x y ) A B C D 4 A P ; B P ; Facebook.com/mathvncom c rỳt gn li l: a Cõu 11: Bit log3 a A B a b ma A log a b a3 C P 22 www.MATHVN.com - Toỏn hc Vit Nam Cõu 15: S nghim ca phng trỡnh 8.3 x x 91 x x l: A B C D Cõu 16 Giỏ tr nh nht ca hm s y f x x ln 2x trờn on 1;0 l: A ln 4 B ln3 D ln5 C Cõu 17: Bit logb a b 0, b 1, a Tớnh biu thc P log 3 a b C B a cú giỏ tr l: b om A D Cõu 18: Mnh no sau õy sai ? A Hm s y 3x l hm s ng bin trờn ; B x lim 3x C th hm s y 3x luụn i qua im 3; thv n.c x D th hm s y 3x v y i xng qua truc tung Cõu 19 Hm s no di õy ng bin trờn xỏc nh ca nú? A y x B y x C y 52 x e D y x Cõu 20 Tp nghim ca phng trỡnh log3 x log5 x log3 x.log5 x l: A 5;15 B 15;1 C 5;1 D 3;5 Cõu 21 Phng trỡnh sau log x 4log3 x log x cú nghim l: 3 C S ;3 B S ; A S ;1 D S ;3 Cõu 22 Cho log a x 2; logb x 4; log c x ú giỏ tr ca biu thc log abc x bng : B ma A C Cõu 23 Tp nghim ca bt phng trỡnh A (1;3) B (; 1) (3; ) D x2 x l C (1 3;1 3) D (;1 3) (1 3; ) Cõu 24: Hm s y log( x x m ) cú xỏc nh l R ; nu: A m (; 3) (3; ) Cõu 25: Bt phng trỡnh: A x 12: B m (3;3) C m [3;3] 21 x x cú nghim l: x2 x B x C x Facebook.com/mathvncom 23 D m (; 3] [3; ) D x www.MATHVN.com - Toỏn hc Vit Nam Cõu Tp xỏc nh ca hm s y log1 x l: B ( ; ) C (0;9) Cõu Tp xỏc nh ca hm s y (4 3x x ) l: D (9; ) A (0; ) B R \ 4;1 A (4;1) D 4;1 C (; 4) (1; ) Cõu Tp xỏc nh ca hm s y (9 x )3 l: B R \ Cõu 4: Tp xỏc nh ca hm s y lg C (;3) (3; ) x2 x l: x A (0;1) (3; ) B (3; ) Cõu 5: o hm ca hm s y log (3x 1) l: A (3x 1) ln B (3x 1) ln D ỏp ỏn khỏc om A R \ C (1;2) \ C 3ln (3x 1) D Cõu 6: Cho f ( x) 2x o hm cp hai f ''(0) bng: A ln B ln C ln 2(1 ln 2) Cõu 7: Cho f ( x) x log x o hm f '(10) bng: A 10 ln10 (3 x 1) ln x thv n.c D (0;1) B ln10 C D ỏp ỏn khỏc 10 ln10 D 10.ln10 Cõu 8: Cho 25 x 25 x 98 Khi ú biu thc M 5x x cú giỏ tr bng: A B C 10 10 Cõu 9: Giỏ tr nh nht ca hm s y x trờn on (1: ) l: ln x e2 A e B C ln Cõu 10: Giỏ tr ln nht ca hm s f x log22 x log2 x l: ma A B D D e D Khụng tn ti C Cõu 11: Giỏ tr ca biu thc P log3 2.log 3.log5 log31 30.log32 31 l: ; D.ỏp ỏn khỏc 32 Cõu 12: Bit a log 24 54 Tớnh theo a biu thc log cú giỏ tr l: a 3a a 3a A B C D 3a a 3a a A P ; B P ; C P Cõu 13: Xỏc nh bt ng thc sai 2016 2017 10 2 A C D Cõu 14: Tng cỏc nghim ca phng trỡnh 16 x 2.4 x1 12 l: B Facebook.com/mathvncom 24 300 301 www.MATHVN.com - Toỏn hc Vit Nam A B 2, 29 C log 12 x x D log x Cõu 15 Bt phng trỡnh: 6.9 13.6 6.4 cú nghim l: A (; 1] [1; ) B [1;1] C (0;1] D [1; ) Cõu 16: Cho s dng a, biu thc a a a5 vit di dng hu t l: C th hm s y 3x luụn i qua im 3; x D a om A a B a C a Cõu 17: Mnh no sau õy sai ? A Hm s y 3x l hm s ng bin trờn ; B x lim 3x thv n.c D th hm s y 3x v y i xng qua truc tung 3 4 3 Cõu 18 Nu a a v log b log b thỡ A a 1;0 b B a 1;0 b C a 1; b D a 1; b Cõu 19 Cho log3 x; log y Tớnh theo x; y thỡ log 829440 bng : A x y B x y C x y D x y Cõu 20 Tng cỏc nghim ca phng trỡnh 810.3x x 59049 l: A B C 84 D 10 x x Cõu 21 Phng trỡnh sau 36 7.6 12 cú nghim l: A 3; B 0,61;0,773 C log6 3;log6 D 1;log6 12 Cõu 22 Cho hm s y ln x x Biu thc 2( x 1) y ' x c rỳt gn li l : A e y C 3e y B 2e2 y D 4e2 y x x ma Cõu 23 Tp nghim ca bt phng trỡnh l A (1;3) B (; 1) (3; ) C (; ) D ỏp ỏn khỏc Cõu 24: Hm s y log[ x 2(m 3) x (m 5)] cú xỏc nh l R ; nu: A m (; 4) (1; ) B m (4; 1) C m (1;4) D m (;1) (4; ) Cõu 25: Bt phng trỡnh: x x log x cú nghim l: A 3; B ; Facebook.com/mathvncom C 4; 25 D 3; [...]... nhau qua truc tung 4 3 Cõu 22 Cho M A M 0 log 5 3.log15 4 Xỏc nh mnh ỳng: 2 log 6 3.log 0,3 7 7 B M 0 C M 0 Cõu 23 Tng cỏc nghim ca phng trỡnh log 2 Facebook.com/mathvncom D M 0 2x 1 2 x 2 6 x 2 l: 2 ( x 1) 10 www.MATHVN.com - Toỏn hc Vit Nam A 2 C log 2 B 0 5 6 125 6 D log 2 x x Cõu 24: Gớa tr no ca m thỡ phng trỡnh 4 15 m 4 15 2 cú hai nghim phõn bit? B 0 m 16 C 0 m 1 1 Cõu... 36 C 1 48 D 37 72 Cõu 4: o hm ca hm s y 4 1 x 2 l: 1 A 4 (1 x ) B 2 3 x 4 1 x C 2 1 4 1 x 4 2 D x 2 4 (1 x 2 )3 ma Cõu 5: o hm ca hm s y x x x x l : A 2x C 1 B 2 x 15 1616 x Cõu 6: o hm ca hm s f x ecos2x ti x 6 D 15 16 16 x15 l: A 3e B 3e C 3e D 3e Cõu 7: Bit a log 2; b log 3 Tớnh theo a, b biu thc log1399680 cú giỏ tr l: A 1 6a 7b B 6a 6b Cõu 8: Tớnh giỏ tr ca biu thc K 81 1... log 3 a log3 a 2 log 1 a 2log3 a cú giỏ tr l: 3 C 5 D 7 log a c log a b c rỳt gn li l: log ab c A 1 B log a b C 1 log a b x Cõu 14: Tng cỏc nghim ca phng trỡnh 4 8.2 x 15 0 l: A 8 B 3,9 C log 2 15 Cõu 13: Biu thc Cõu 15 Bit x 2 4 y 2 5xy; x, y 0 Giỏ tr biu thc M Facebook.com/mathvncom D 20 D 1 D log 2 5 3 log 2 x log 2 y l: log 2 ( x 2 y ) www.MATHVN.com - Toỏn hc Vit Nam A 1 B 2 C... Toỏn hc Vit Nam 1 2 Cõu 13 Tp nghim ca bt phng trỡnh ( ) x 7 x 12 1 l 4 A (;3) (4; ) ; B (3; 4) C (;0) (3; ) Cõu 14: Biu thc D (0;3) x x x x (x > 0) vit di dng lu tha vi s m hu t l: 15 16 3 8 1 16 A x B x C x Cõu 15: Cho log 214 a Khi ú log 49 32 tớnh theo a l: 5 2(a 1) B 5 2 a C 5 1 2a D 5 2 3a om A D x 5 4 5 3x 3 x cú giỏ tr bng: 1 3x 3 x 5 3 1 A B 2 C D 2 2 4 2 x 1 x Cõu 17: Phng... a Cõu 7: Biu thc A 1 a 3 1 a 2 1 3 1 a x D 4e x D 3; C ; 3 (4; ) 3 3 1 a 2 3 C a 2 B a x3 l: 4 x C 3e c rỳt gn li l: D ỏp ỏn khỏc Cõu 8: Giỏ tr ca biu thc P log3 2.log 4 3.log5 4 log15 14.log16 15 l: 1 4 B P ; ma A P 1 ; C P 2 ; D P 17 201 1 Cõu 9: Giỏ tr ln nht ca hm s y f x 2x2 ln x trờn on ; e l: e 2 1 A 2 1 B 2 C ln 2 D 2e 2 1 e 2 Cõu 10: Bit a log 20 3; b log 20 5;... 2a b 2c B 1 a 2b 2c Cõu 12: Khng nh no sau l sai ? C 1 2a 2b c Facebook.com/mathvncom 15 D 2 a b c www.MATHVN.com - Toỏn hc Vit Nam A log3 5 0 B log x 2 3 1 2016 log x2 3 2017 C log 3 4 log 3 3 D log 0,3 2016 0 2017 1 C th hm s y 2 x luụn i qua im 2; 4 1 x om Cõu 13: Cho ba s a log15 14; b log7 8; c log6 37 Bt ng thc no sau õy ỳng ? A a b c B a c b C c b a D b a... Cõu 15: Chn mnh ỳng trong cỏc mnh sau: 1,4 3 A 4 2 B 3 3 4 3 1,7 1 C 3 1 3 2 2 2 D 3 3 Cõu 16 S no di õy ln hn 0 nhng nh hn 1? A (0,7)2017 C (0,7)2017 B (1, 7)2017 e thv n.c D ỏp ỏn khỏc Cõu 17: : S nghim ca phng trỡnh 5 9.5 27(5 5 ) 64 l: A 1 B 2 C 3 D 4 x x1 Cõu 18 Tng cỏc nghim ca phng trỡnh log 5 (5 1) log 25 (5 5) 1 l: 3x A log5 6 3 x x B log5 126 C log 5 x 156 ... xng nhau qua truc tung 3 Cõu 19 Hm s no di õy ng bin trờn tp xỏc nh ca nú? 1 A y 3 1 x 3 B y 4 x C y 52 x e D y x Cõu 20 Tp nghim ca phng trỡnh log3 x log5 x log3 x.log5 x l: A 5 ;15 B 15; 1 C 5;1 D 3;5 Cõu 21 Phng trỡnh sau log 2 3 x 4log3 x log 1 x 1 cú tp nghim l: 3 1 3 1 4 1 3 C S 4 ;3 B S ; 4 3 A S ;1 1 4 D S ;3 Cõu 22 Cho log a x 2; logb x 4; log c... www.MATHVN.com - Toỏn hc Vit Nam Cõu 13: Cõu 16: S nghim ca phng trỡnh 9x 1 36.3x 3 3 0 l: A 1 B 2 C 3 D 4 e e Cõu 14: Cho Kt lun no sau õy l ỳng? 3 3 A < B > C + = 0 D . = 1 2 2 Cõu 15: o hm ca hm s y ln x x 2 1 l: 1 B x x2 1 2x 2x C ( x 2 1)3 1 x x2 1 1 3 D 1 x2 1 om A thv n.c Cõu 16 Tp nghim ca bt phng trỡnh 3 x 3 x 84 l A 1 x 0 ; B (;0) (1; ) ; C 0 x 1 ; D 1 x... no l khng nh sai: A log 2 5 1 B log 2 3 5 log 3 11 4 7 C log 1 7 0 D log 2 ( 2 1) 0 2 Cõu 14: Tng cỏc nghim ca phng trỡnh log 2 x 2log7 x 2 log 2 x.log 7 x l: A 10 B 11 C 12 D ỏp s khỏc 3 Cõu 15: Nghim x0 ca phng trỡnh log2 (1 x ) log7 x nm trong khong no sau õy? A 1 x0 5 B 20 x0 50 C 100 x0 200 D 300 x0 400 Cõu 16 Cho a log 3 Khi ú log 9000 tớnh theo a l: ma A 2a 3 B a 2 3 C