4.求函数y=lg(x2+x-6)的单调增区间是( )
A. | $(-∞,-\frac{1}{2})$ | B. | $(-\frac{1}{2},+∞)$ | C. | (2,+∞) | D. | (-∞,-3) |
19.已知倾斜角为α的直线l与直线x+2y-3=0垂直,则cos($\frac{2015π}{2}$-2α)的值为( )
A. | $\frac{4}{5}$ | B. | -$\frac{4}{5}$ | C. | 2 | D. | -$\frac{1}{2}$ |
18.已知几何体的三视图如图所示,则该几何体的表面积为( )
A. | 4+$\sqrt{6}$ | B. | 6+$\sqrt{6}$ | C. | 2+2$\sqrt{2}$+$\sqrt{6}$ | D. | 2+2$\sqrt{3}$+$\sqrt{6}$ |
17.若复数z=$\frac{a-i}{1-i}$(a∈R,i是虚数单位)是纯虚数,则复数3-z的共轭复数是( )
A. | 3+i | B. | 3-i | C. | 3+2i | D. | 2-i |
16.已知集合A={0,1,2,3,4,5},B={x|x2-7x+10<0},则A∩B的子集可以是( )
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A. | {3,4,5} | B. | {4,5} | C. | {3,5} | D. | {4} |