6.下列命题正确的是( )
| A. | 若p,q为两个命题,则“p且q为真”是“p或q为真”的必要不充分条件 | |
| B. | 若p为:?x∈R,x2+2x≤0则¬p为:?x∈R,x2+2x>0 | |
| C. | 命题p为真命题,命题q为假命题.则命题p∧(¬q),(¬p)∨q都是真命题 | |
| D. | 命题“若¬p,则q”的逆否命题是“若p,则¬q”. |
5.过圆x2+y2=4外一点P作该圆的切线,切点为A、B,若∠APB=60°,则点P的轨迹是( )
| A. | 直线 | B. | 圆 | C. | 椭圆 | D. | 抛物线 |
3.在平面直角坐标系xOy中,已知点A(4,3),点B是圆(x+1)2+y2=4上的动点,则线段AB的中点M的轨迹方程是( )
| A. | ${(x-\frac{3}{2})^2}+{(y-\frac{3}{2})^2}=1$ | B. | ${(x-\frac{3}{2})^2}+{(y-\frac{3}{2})^2}=4$ | C. | (x-3)2+(y-3)2=1 | D. | (x-3)2+(y-3)2=2 |
20.已知函数f(x)=$\sqrt{3}$sinωx+cosωx(ω>0)的最小正周期为π,把函数f(x)的图象沿x轴向左平移$\frac{π}{6}$个长度单位,得到函数g(x)的解析式为( )
| A. | g(x)=2sin(2x+$\frac{2π}{3}$) | B. | g(x)=2sin(2x-$\frac{π}{6}$) | C. | g(x)=2sin2x | D. | g(x)=2cos2x |
19.命题“?x∈R,x2≠x”的否定是( )
0 226795 226803 226809 226813 226819 226821 226825 226831 226833 226839 226845 226849 226851 226855 226861 226863 226869 226873 226875 226879 226881 226885 226887 226889 226890 226891 226893 226894 226895 226897 226899 226903 226905 226909 226911 226915 226921 226923 226929 226933 226935 226939 226945 226951 226953 226959 226963 226965 226971 226975 226981 226989 266669
| A. | ?x0∈R,x${\;}_{0}^{2}$=x0 | B. | ?x∈R,x2=x | C. | ?x0∉R,x${\;}_{0}^{2}$≠x0 | D. | ?x∉R,x2≠x |