16.
如图所示,在Rt△ABC中,∠BAC=90°,AB=2,BC=4,BD=$\frac{1}{4}$BC,E是AD的中点,则$\overrightarrow{CE}$$•\overrightarrow{AB}$的值是( )
| A. | 3 | B. | $\sqrt{3}$ | C. | 2$\sqrt{3}$ | D. | $\frac{3}{2}$ |
15.已知函数f(x)=sin(ωx-$\frac{π}{6}$)(ω>0),x∈R.,f(α)=-1,f(β)=0,若|α-β|的最小值为$\frac{3π}{4}$,则函数f(x)的单调递增区间为( )
| A. | [-$\frac{π}{2}$+2kπ,π+2kπ],k∈Z | B. | [-$\frac{π}{2}$+3kπ,π+3kπ],k∈Z | ||
| C. | [π+2kπ,$\frac{5}{2}$π+2kπ],k∈Z | D. | [π+3kπ,$\frac{5}{2}$π+3kπ],k∈Z |
14.若非零向量$\overrightarrow{a}$,$\overrightarrow{b}$满足|$\overrightarrow{a}$|=$\frac{\sqrt{2}}{2}$|$\overrightarrow{b}$|,且($\overrightarrow{a}$-$\overrightarrow{b}$)⊥(3$\overrightarrow{a}$+2$\overrightarrow{b}$),则$\overrightarrow{a}$与$\overrightarrow{b}$的夹角为( )
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| A. | $\frac{π}{4}$ | B. | $\frac{π}{2}$ | C. | $\frac{2π}{3}$ | D. | $\frac{3π}{4}$ |