GROUP NHÓM TOÁN THI THPT 2017 LÔGARIT 02 S nghi m c A B C log x log3 y D x 2y log y log3 x A B C 39 D A B C D A B C D A C T A 1; A -1 x x ln nh c a hàm s B x 1; 2 C là: 1; C B D 1; D log ( x x) log (2 x 3) A B C y2 2x 4x y D B A T C nh c a hàm s là: A B C D a3 a 2 log b log b A B C D A 3log(a b) (log a log b) B log(a b) D log C T p nghi m c a b A D 1;1 a b 3 (log a log b) (log a log b ) : B 1;0 C 0;1 có hai nghi m x1 , x2 th a x1 x2 D A C m B A B C D A C o hàm c a hàm s y 2x : 5x D 1;1 A C x x ln x ln 5 x x B x D 23 x 6.2 x x ln 5 x x x ln x 12 2x 3( x 1) B A x C D Tính log 36 24 theo log 12 27 a A a 2a A B a 2a a 2a C B C D a 2a D Tính log 30 1350 theo a, b v i log 30 a log30 b A C a 2b B 5 x y xy Rút g n bi u th c (x, y 0) x y A 2xy A -9 c k t qu là: B xy B -1 4 x2 2.2x B C D Nghi m c A x2 C A D xy xy C 22 x Tích hai nghi m c D là: D B C D A B C D A C Rút g n bi u th c A a4 (a a 2 ) 2 (a 0) B a 10 c k t qu C a5 D a3 o hàm c a hàm s : y (x x) là: A (x x) C a (x x) y 1 (2 x 1) B (x x) D (x x) (2 x 1) ln x x A B C D A -3 B C -1 D A -1 C u ki n c a bi u th c t n t i, k t qu rút g n c a A B C D A B D x > C x A x 2 x C N u a a logb logb : B C.a>1,b>1 C 01,0