15.F1,F2为双曲线的两个焦点,以F2为圆心作圆,已知圆F2经过双曲线的中心,且与双曲线相交于M点,若直线MF1恰与圆F2相切,则该双曲线的离心率e为( )
| A. | $\sqrt{2}$+1 | B. | $\sqrt{3}$+2 | C. | $\sqrt{2}$+2 | D. | $\sqrt{3}$+1 |
14.直线l与抛物线y2=4x相交于A,B两点,且线段AB的中点为(1,1),则l的方程为( )
| A. | 2x-y-1=0 | B. | 2x+y-3=0 | C. | x-2y+1=0 | D. | x+2y-3=0 |
13.圆x2+y2-2x-4y-20=0过点(1,-1)的最大弦长为m,最小弦长为n,则m+n=( )
| A. | 17 | B. | 18 | C. | 19 | D. | 20 |
12.过点A(5,2),且在坐标轴上截距的绝对值相同的直线l的方程为( )
0 234176 234184 234190 234194 234200 234202 234206 234212 234214 234220 234226 234230 234232 234236 234242 234244 234250 234254 234256 234260 234262 234266 234268 234270 234271 234272 234274 234275 234276 234278 234280 234284 234286 234290 234292 234296 234302 234304 234310 234314 234316 234320 234326 234332 234334 234340 234344 234346 234352 234356 234362 234370 266669
| A. | x-y-3=0 | B. | 2x-5y=0 | ||
| C. | x-y-3=0或2x-5y=0 | D. | x-y-3=0或2x-5y=0或x+y-7=0 |