20.下列关于函数f(x)=-2sin2x-cos4x(x∈R)的说法正确的是( )
A. | f(x)的最小正周期为2π | B. | f(x)的最大值为-1 | ||
C. | f(x)是偶函数 | D. | f(x)在[$\frac{π}{12}$,$\frac{π}{4}$]上单调增 |
18.极坐标系中,曲线θ=$\frac{2π}{3}$与ρ=6sinθ的两个交点之间的距离为( )
A. | 1 | B. | $\sqrt{3}$ | C. | 3$\sqrt{3}$ | D. | 6 |
17.函数f(x)对任意的a,b∈R,都有f(a+b)=f(a)+f(b)-1,并且当x>0时f(x)>1,
(1)求证:f(x)在R上是增函数;
(2)若f(2)=3,解不等式f(3m2-m-2)<3.
(1)求证:f(x)在R上是增函数;
(2)若f(2)=3,解不等式f(3m2-m-2)<3.
15.能化为普通方程x2+y-1=0的参数方程是( )
0 247727 247735 247741 247745 247751 247753 247757 247763 247765 247771 247777 247781 247783 247787 247793 247795 247801 247805 247807 247811 247813 247817 247819 247821 247822 247823 247825 247826 247827 247829 247831 247835 247837 247841 247843 247847 247853 247855 247861 247865 247867 247871 247877 247883 247885 247891 247895 247897 247903 247907 247913 247921 266669
A. | $\left\{\begin{array}{l}x=sint\\ y={cos^2}t\end{array}\right.$ | B. | $\left\{\begin{array}{l}x=tanφ\\ y=1-{tan^2}φ\end{array}\right.$ | ||
C. | $\left\{\begin{array}{l}x=\sqrt{1-t}\\ y=t\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x=cosθ}\\{y=si{n}^{2}θ}\end{array}\right.$ |