12.已知直线y=m(0<m<2)与函数y=sinωx+$\sqrt{3}$cosωx(ω>0)的图象依次交于A(1,m),B(5,m),C(7,m)三点,则ω=( )
| A. | $\frac{π}{3}$ | B. | $\frac{π}{4}$ | C. | $\frac{π}{2}$ | D. | $\frac{π}{6}$ |
5.
如图,直三棱柱ABC-A1B1C1中,D、E分别是AB、BB1的中点.
(Ⅰ)证明:BC1∥平面A1CD;
(Ⅱ)设AA1=AC=CB=2,AB=2$\sqrt{2}$,求四棱锥C-A1ABE的体积.
0 252660 252668 252674 252678 252684 252686 252690 252696 252698 252704 252710 252714 252716 252720 252726 252728 252734 252738 252740 252744 252746 252750 252752 252754 252755 252756 252758 252759 252760 252762 252764 252768 252770 252774 252776 252780 252786 252788 252794 252798 252800 252804 252810 252816 252818 252824 252828 252830 252836 252840 252846 252854 266669
(Ⅰ)证明:BC1∥平面A1CD;
(Ⅱ)设AA1=AC=CB=2,AB=2$\sqrt{2}$,求四棱锥C-A1ABE的体积.