10.已知椭圆过点(0,3)且与双曲线$\frac{{x}^{2}}{9}-\frac{{y}^{2}}{7}$=1有相同的焦点,则椭圆的标准方程为( )
| A. | $\frac{{x}^{2}}{7}+\frac{{y}^{2}}{9}$=1 | B. | $\frac{{x}^{2}}{9}+\frac{{y}^{2}}{7}$=1 | C. | $\frac{{x}^{2}}{16}+\frac{{y}^{2}}{7}$=1 | D. | $\frac{{x}^{2}}{25}+\frac{{y}^{2}}{9}$=1 |
9.若命题p的否命题是命题q,命题q的逆否命题是命题r,则命题r是命题p的( )
| A. | 原命题 | B. | 逆命题 | C. | 否命题 | D. | 逆否命题 |
8.设椭圆$\frac{{x}^{2}}{9}+\frac{{y}^{2}}{4}$=1,则该椭圆的焦点坐标为( )
| A. | (-$\sqrt{5}$,0),($\sqrt{5}$,0) | B. | (0,-$\sqrt{5}$),(0,$\sqrt{5}$) | C. | (-$\sqrt{13}$,0),($\sqrt{13}$,0) | D. | (0,-$\sqrt{13}$),(0,$\sqrt{13}$) |
7.三个数0.76,60.7,log0.7 6的大小关系为( )
| A. | log0.7 6<0.7 6<6 0.7 | B. | 0.7 6<6 0.7<log0.7 6 | ||
| C. | log0.7 6<6 0.7<0.76 | D. | 0.7 6<log0.7 6<6 0.7 |
6.已知向量$\overrightarrow{a}$,$\overrightarrow{b}$满足|$\overrightarrow{a}$|=2,|$\overrightarrow{b}$|=1,$\overrightarrow{a}•\overrightarrow{b}$=1,则向量$\overrightarrow{a}$与$\overrightarrow{a}-\overrightarrow{b}$的夹角为( )
| A. | $\frac{π}{6}$ | B. | $\frac{π}{3}$ | C. | $\frac{5π}{6}$ | D. | $\frac{2π}{3}$ |
5.已知$\overrightarrow a=(-2,4),\overrightarrow b=(x,-2),且\overrightarrow a∥\overrightarrow b,则x的值为$( )
0 234719 234727 234733 234737 234743 234745 234749 234755 234757 234763 234769 234773 234775 234779 234785 234787 234793 234797 234799 234803 234805 234809 234811 234813 234814 234815 234817 234818 234819 234821 234823 234827 234829 234833 234835 234839 234845 234847 234853 234857 234859 234863 234869 234875 234877 234883 234887 234889 234895 234899 234905 234913 266669
| A. | -1 | B. | 0 | C. | 1 | D. | 2 |