19.点P(1,-2)关于点M(3,0)的对称点Q的坐标是( )
A. | (1,2) | B. | (2,-1) | C. | (3,-1) | D. | (5,2) |
13.设f(x)是定义在R上的偶函数,对任意x∈R,都有f(x-2)=f(x+2),且当x∈[-2,0]时,$f(x)={(\frac{1}{2})^x}$-1,若在区间(-2,10]内,关于x的方程f(x)-loga(x+2)=0(a>1)恰有5个不同的实数根,则a的取值范围是( )
A. | $(2,\root{3}{12})$ | B. | $(\root{3}{4},2\sqrt{2})$ | C. | $(\root{3}{4},2)$ | D. | (2,+∞) |
12.设$a={0.6^{\frac{1}{2}}}$,$b={0.7^{\frac{1}{2}}}$,c=lg0.7,则( )
A. | c<b<a | B. | b<a<c | C. | c<a<b | D. | a<b<c |
11.已知等差数列{an}的公差d=-2,a1+a4+a7+…+a97=50,那么a3+a6+a9+…+a99的值是( )
0 250842 250850 250856 250860 250866 250868 250872 250878 250880 250886 250892 250896 250898 250902 250908 250910 250916 250920 250922 250926 250928 250932 250934 250936 250937 250938 250940 250941 250942 250944 250946 250950 250952 250956 250958 250962 250968 250970 250976 250980 250982 250986 250992 250998 251000 251006 251010 251012 251018 251022 251028 251036 266669
A. | -78 | B. | -82 | C. | -148 | D. | -182 |