16.下列函数中,能用二分法求零点的是( )
A. | f(x)=log2x | B. | f(x)=-x2 | C. | f(x)=x2 | D. | f(x)=|x| |
15.已知全集U={1,2,3,4,5,6,7},A={1,3,5},B={2,4,5,7},则集合∁U(A∪B)为( )
A. | {1,2,3,4,6,7} | B. | {1,2,5} | C. | {3,5,7} | D. | {6} |
11.方程sin2x+sin x-1-m=0在实数集上有解,则实数m的范围为( )
A. | $[-\frac{5}{4},+∞)$ | B. | $[-\frac{5}{4},1]$ | C. | $(-∞,-\frac{5}{4}]$ | D. | [-1,$\frac{5}{4}$] |
8.已知变量x,y满足约束条件$\left\{\begin{array}{l}x+y≥0\\ x-2y+2≥0\\ x-y≤0\end{array}\right.$,则z=2x-y的最大值为( )
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A. | -2 | B. | -1 | C. | 2 | D. | 1 |