15.若复数$\frac{1-bi}{2+i}$(b∈R)的实部与虚部相等,则b的值为( )
| A. | -6 | B. | -3 | C. | 3 | D. | 6 |
11.定义在(-2,2)上的偶函数f(x),当x≥0时,f(x)为减函数,若f(m-1)<f(-m),则实数m的取值范围是( )
| A. | $({-1,\frac{1}{2}})$ | B. | $({-∞,\frac{1}{2}})$ | C. | $({\frac{1}{2},2})$ | D. | $[{-1,\frac{1}{2}})$ |
10.已知函数f(x)=$\frac{1}{{\sqrt{2-x}}}+\sqrt{x+2}$的定义域为( )
0 234573 234581 234587 234591 234597 234599 234603 234609 234611 234617 234623 234627 234629 234633 234639 234641 234647 234651 234653 234657 234659 234663 234665 234667 234668 234669 234671 234672 234673 234675 234677 234681 234683 234687 234689 234693 234699 234701 234707 234711 234713 234717 234723 234729 234731 234737 234741 234743 234749 234753 234759 234767 266669
| A. | {x|x≥-2} | B. | {x|x<2} | C. | {x|-2<x<2} | D. | {x|-2≤x<2} |