10.已知函数f(x)=x+3ex,若方程f2(x)-2|f(x)|=0的根有( )
| A. | 0个 | B. | 1个 | C. | 2个 | D. | 3个 |
9.已知数列{an}满足$\frac{a_1}{2}•\frac{a_2}{5}•\frac{a_3}{8}…\frac{a_n}{3n-1}=3n+2(n∈{N^*})$,Sn为{an}的前n项和,则S10=( )
| A. | 210 | B. | 180 | C. | 185 | D. | 190 |
8.已知偶函数f(x)满足f(4+x)=f(4-x),且当x∈(0,4]时,f(x)=$\frac{{ln({2x})}}{x}$,关于x的不等式f2(x)+af(x)>0在[-200,200]上有且只有200个整数解,则实数a的取值范围是( )
| A. | $({-\frac{1}{3}ln6,ln2}]$ | B. | $({-ln2,-\frac{1}{3}ln6})$ | C. | $({-ln2,-\frac{1}{3}ln6}]$ | D. | $({-\frac{1}{3}ln6,ln2})$ |
4.在△ABC中,角A、B、C分别对应边a,b,c.若9a2+9b2-19c2=0,求$\frac{\frac{1}{tanC}}{\frac{1}{tanA}+\frac{1}{tanB}}$的值.
0 240613 240621 240627 240631 240637 240639 240643 240649 240651 240657 240663 240667 240669 240673 240679 240681 240687 240691 240693 240697 240699 240703 240705 240707 240708 240709 240711 240712 240713 240715 240717 240721 240723 240727 240729 240733 240739 240741 240747 240751 240753 240757 240763 240769 240771 240777 240781 240783 240789 240793 240799 240807 266669