Page 30 - CHƯƠNG II: GIẢI TÍCH 12-12a2

Trường THPT Châu Phú Chương II: Mũ – Lôgarit INOXHTT
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Câu 213: Nếu log 243 5 thì x bằng:
x
A. 2 B. 3 C. 4 D. 5
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x
x +
Câu 214: Cho biểu thức B = 3log x − 6log (3 ) log . Giá trị lớn nhất của B với (log x )  2;3 − 
3 9 1 9 3
3
. A B = − 1 . B B = − 2 C .B = 1 D .B =
2
( 3 1 − ) 2 − 2 3
Câu 215 Rút gọn biểu thức b : b (b > 0), ta đợc:
4
2
3
A. b B. b C. b D. b

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Câu 216: Cho f(x) = x x x . Khi đó f(2,7) bằng:
5
3
4
12
A. 2,7 B. 3,7 C. 4,7 D. 5,7

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Câu 217: Cho lg2 = a. Tính lg25 theo a?
A. 2 + a B. 2(2 + 3a) C. 2(1 - a) D. 3(5 - 2a)

x
x +
Câu 236: Cho biểu thức B = 3log x − 6log (3 ) log . Xác định x biết B = 2
3 9 1 9
3
1 1 2 2
. A x = − . B x = . C x = − . D x =
27 27 27 27
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11
Câu 237: Rút gọn biểu thức: x x x x : x , ta được:
16
A. x B. x C. x D. x
6
8
4

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