4.已知f(x)是定义在R上的偶函数,且在(-∞,0)上单调递增,a=f(0.80.8),b=f(0.81.6),c=f(1.60.8),则a,b,c的大小关系是( )
| A. | c<a<b | B. | a<c<b | C. | a<b<c | D. | c<b<a |
3.对任意正数x,不等式x-2a>2-x恒成立,则a的取值范围为( )
| A. | $(-∞,-\frac{1}{2})$ | B. | $(-1,-\frac{1}{2})$ | C. | $(-\frac{1}{2},0)$ | D. | $(-∞,-\frac{1}{2}]$ |
2.某几何体的三视图如图所示,则该几何体的表面积为( )

| A. | 36 | B. | $54+6\sqrt{13}$ | C. | $54+12\sqrt{5}$ | D. | $30+6\sqrt{73}$ |
1.已知函数$f(x)=\left\{\begin{array}{l}{2^x}-1,x≥0\\{log_2}|x|,x<0\end{array}\right.$,若f(a)+f(1)=4,则a等于( )
0 226710 226718 226724 226728 226734 226736 226740 226746 226748 226754 226760 226764 226766 226770 226776 226778 226784 226788 226790 226794 226796 226800 226802 226804 226805 226806 226808 226809 226810 226812 226814 226818 226820 226824 226826 226830 226836 226838 226844 226848 226850 226854 226860 226866 226868 226874 226878 226880 226886 226890 226896 226904 266669
| A. | -8 | B. | -6 | C. | 2或-8 | D. | 2或-6 |