5.函数y=2sin$\frac{x}{2}$+1的图象的一条对称轴方程是( )
A. | x=$\frac{π}{2}$+1 | B. | x=$\frac{π}{2}$ | C. | x=π+1 | D. | x=π |
1.已知实数x、y满足约束条件$\left\{\begin{array}{l}{y≤-x+2}\\{y≤x-1}\\{y≥0}\end{array}\right.$,则其围成的平面区域的面积为( )
A. | 1 | B. | $\frac{1}{2}$ | C. | $\frac{1}{3}$ | D. | $\frac{1}{4}$ |
20.已知在△ABC中,角A、B、C成公差大于0的等差数列,且满足条件:1-cos2A-cos2C+cos2Acos2C=$\frac{4+2\sqrt{3}}{4}$,则$\frac{a+\sqrt{2}b}{c}$的值为( )
A. | $\frac{\sqrt{6}+1}{2}$ | B. | $\frac{\sqrt{6}+\sqrt{2}}{4}$ | C. | $\frac{2+\sqrt{3}}{4}$ | D. | 2 |
18.若sinα=1-$\sqrt{3}$tan10°sinα,则锐角α的值为( )
A. | 40° | B. | 50° | C. | 60° | D. | 70° |
17.计算:cos75°cos15°-sin75°sin15°的值为( )
0 245630 245638 245644 245648 245654 245656 245660 245666 245668 245674 245680 245684 245686 245690 245696 245698 245704 245708 245710 245714 245716 245720 245722 245724 245725 245726 245728 245729 245730 245732 245734 245738 245740 245744 245746 245750 245756 245758 245764 245768 245770 245774 245780 245786 245788 245794 245798 245800 245806 245810 245816 245824 266669
A. | 0 | B. | 1 | C. | $\frac{1}{2}$ | D. | $\frac{\sqrt{3}}{2}$ |