4.已知双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}=1\;(a>0,b>0)$与函数$y=\sqrt{x}(x≥0)$的图象交于点P,若函数$y=\sqrt{x}$在点P处的切线过双曲线左焦点F(-1,0),则双曲线的离心率是( )
| A. | $\frac{{\sqrt{5}+1}}{2}$ | B. | $\frac{{\sqrt{5}+3}}{2}$ | C. | $\frac{{\sqrt{3}+1}}{2}$ | D. | $\frac{3}{2}$ |
1.已知实数x,y满足不等式组$\left\{\begin{array}{l}x-3y+5≥0\\ 2x+y-4≤0\\ y+2≥0\end{array}\right.$则z=x+y的最小值为-13.
19.已知直线l与双曲线$\frac{x^2}{4}-{y^2}=1$相切于点P,l与双曲线两条渐进线交于M,N两点,则$\overrightarrow{OM}•\overrightarrow{ON}$的值为( )
| A. | 3 | B. | 4 | C. | 5 | D. | 与P的位置有关 |
16.已知$\frac{\overline z}{1+i}=2+i$,则复数z=( )
| A. | 1-3i | B. | -1-3i | C. | -1+3i | D. | 1+3i |
15.甲、乙、丙3名学生排成一排,其中甲、乙两人站在一起的概率是( )
0 238339 238347 238353 238357 238363 238365 238369 238375 238377 238383 238389 238393 238395 238399 238405 238407 238413 238417 238419 238423 238425 238429 238431 238433 238434 238435 238437 238438 238439 238441 238443 238447 238449 238453 238455 238459 238465 238467 238473 238477 238479 238483 238489 238495 238497 238503 238507 238509 238515 238519 238525 238533 266669
| A. | $\frac{1}{6}$ | B. | $\frac{1}{3}$ | C. | $\frac{2}{3}$ | D. | $\frac{1}{2}$ |