3.已知抛物线C:y2=4x的焦点为F,准线为l,在抛物线C上取一点A,过A分别向x轴和准线作垂线,垂足分别为M,N,连接AF并延长交抛物线于另一点B,若$\sqrt{5}$AM=2AN,则线段AB的长为( )
| A. | 20 | B. | 40 | C. | 5 | D. | 4 |
20.已知点Q(x0,1),若在圆O:x2+y2=1上存在点P,使得∠OQP=60°,则x0的取值范围是( )
| A. | [-$\frac{1}{3}$,$\frac{1}{3}$] | B. | [-$\frac{1}{2}$,$\frac{1}{2}$] | C. | [-$\frac{\sqrt{2}}{2}$,$\frac{\sqrt{2}}{2}$] | D. | [-$\frac{\sqrt{3}}{3}$,$\frac{\sqrt{3}}{3}$] |
19.若sinα+2sin2$\frac{α}{2}$=2(0<α<π),则tanα的值为( )
| A. | 1 | B. | $\sqrt{3}$ | C. | $\frac{\sqrt{2}}{2}$ | D. | 不存在 |
18.设x,y满足约束条件$\left\{\begin{array}{l}{x≥0}\\{2x-y≤0}\\{x+y-6≤0}\end{array}\right.$,则z=4x-y的最大值为( )
| A. | -6 | B. | 0 | C. | 4 | D. | 6 |
17.设集合A={x∈Z|0≤x<3},集合B={x∈Z|x2≤1},则A∩B=( )
0 229075 229083 229089 229093 229099 229101 229105 229111 229113 229119 229125 229129 229131 229135 229141 229143 229149 229153 229155 229159 229161 229165 229167 229169 229170 229171 229173 229174 229175 229177 229179 229183 229185 229189 229191 229195 229201 229203 229209 229213 229215 229219 229225 229231 229233 229239 229243 229245 229251 229255 229261 229269 266669
| A. | {0,1,2} | B. | {0,1} | C. | [0,1] | D. | {-1,0,1,2} |