14.不等式|x-5|+|x+1|<8的解集为( )
A. | (-∞,2) | B. | (-2,6) | C. | (6,+∞) | D. | (-1,5) |
13.已知:sin($\frac{π}{2}$+θ)+3cos(π-θ)=sin(-θ),则sinθcosθ+cos2θ=( )
A. | $\frac{1}{5}$ | B. | $\frac{2}{5}$ | C. | $\frac{\sqrt{5}}{5}$ | D. | $\frac{3}{5}$ |
12.已知指数函数y=f(x)的图象过点($\frac{1}{2}$,$\frac{\sqrt{2}}{2}$),则log2f(2)的值为( )
A. | $\frac{1}{2}$ | B. | -$\frac{1}{2}$ | C. | -2 | D. | 2 |
10.已知$f(\sqrt{x}-1)=x-2\sqrt{x}$,且f(a)=8,则实数a的值是( )
A. | ±3 | B. | 16 | C. | -3 | D. | 3 |
9.已知幂函数y=f(x)的图象过点$({3,\sqrt{3}})$,则log2f(2)的值为( )
A. | $\frac{1}{2}$ | B. | $-\frac{1}{2}$ | C. | 1 | D. | -1 |
8.下列函数中,既是偶函数,又在区间(0,+∞)上单调递减的是( )
A. | $y=\frac{1}{x}$ | B. | y=-2|x| | C. | $y={log_3}{x^2}$ | D. | y=x-x2 |
7.函数$f(x)=\frac{x^2}{{\sqrt{2-x}}}+lg(x+3)$的定义域为( )
A. | (-3,2] | B. | [-3,2] | C. | (-3,2) | D. | (-∞,-3) |
6.已知集合U={x|0≤x≤6,x∈N},A={2,3,6},B={2,4,5},则A∩(∁UB)=( )
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A. | {2,3,4,5,6} | B. | {3,6} | C. | {2} | D. | {4,5} |