10.已知x,y满足约束条件$\left\{\begin{array}{l}{x,y≥0}\\{x-y≥-1}\\{x+y≤3}\end{array}\right.$,则目标函数z=x-y的最小值为( )
| A. | -4 | B. | -3 | C. | -1 | D. | 3 |
9.将函数f(x)=2sin($\frac{x}{3}$+$\frac{π}{6}$)的图象向左平移$\frac{π}{4}$个单位,再向上平移3个单位,得到函数g(x)的图象,则g(x)的解析式为( )
| A. | g(x)=2sin($\frac{x}{3}$-$\frac{π}{4}$)-3 | B. | g(x)=2sin($\frac{x}{3}$+$\frac{π}{4}$)+3 | C. | g(x)=2sin($\frac{x}{3}$-$\frac{π}{12}$)+3 | D. | g(x)=2sin($\frac{x}{3}$-$\frac{π}{12}$)-3 |
8.已知集合A={x|log2(x+1)<2},B={x|(x-1)(x-3)=0},则A∪B等于( )
| A. | (-1,3) | B. | (-1,3] | C. | (1,3) | D. | (1,3] |
7.若复数z满足z+|z|=3-$\sqrt{3}$i,则z的实部为( )
| A. | 1 | B. | -1 | C. | 3 | D. | -3 |
4.新定义运算:$|\begin{array}{l}{a}&{b}\\{c}&{d}\end{array}|$=ad-bc,则满足$|\begin{array}{l}{i}&{z}\\{-1}&{z}\end{array}|$=-2的复数z的虚部是( )
| A. | -1+i | B. | i | C. | 1 | D. | -i |
1.已知a,b,c为△ABC的三个角A,B,C所对的边,若3bcosC=c(1-3cosB),sinC:sinA=( )
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| A. | 2:3 | B. | 4:3 | C. | 3:1 | D. | 3:2 |