6.已知函数f(x)是定义在R上的偶函数,且对任意x1,x2∈(0,+∞)都有$\frac{f({x}_{1})-f({x}_{2})}{{x}_{1}-{x}_{2}}$<0(x1≠x2),若实数a满足f(log3a-1)+2f(log${\;}_{\frac{1}{3}}$a)≥3f(1),则a的取值范围是( )
| A. | [$\frac{1}{3}$,3] | B. | [1,3] | C. | (0,$\frac{1}{3}$) | D. | (0,3] |
5.函数y=log${\;}_{\frac{1}{3}}$(1-3x)的值域为( )
| A. | (-∞,+∞) | B. | (-∞,0) | C. | (0,+∞) | D. | (1,+∞) |
4.函数f(x)满足f(x)=$\left\{\begin{array}{l}{lo{g}_{2}(3-x),x≤0}\\{f(x-2),x>0}\end{array}\right.$,则f(3)的值为 ( )
| A. | -1 | B. | -2 | C. | 1 | D. | 2 |
3.已知a=log${\;}_{\frac{1}{2}}$5,b=($\frac{1}{3}$)0.3,c=2${\;}^{\frac{1}{5}}$,则( )
| A. | a<b<c | B. | c<b<a | C. | c<a<b | D. | b<a<c |
2.过点(1,2),且倾斜角为60°的直线方程是( )
| A. | y+2=$\sqrt{3}$(x+1) | B. | y-2=-$\sqrt{3}$(x-1) | C. | y-2=$\sqrt{3}$(x-1) | D. | y+2=-$\sqrt{3}$(x+1) |
1.已知两条直线l1:x+2ay-1=0,l2:2x-5y=0,且l1⊥l2,则满足条件a的值为( )
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| A. | $\frac{1}{5}$ | B. | -$\frac{1}{5}$ | C. | -5 | D. | 5 |