1.设f(x)=$\left\{\begin{array}{l}{{x}^{2}+2,x<0}\\{x+1,x≥0}\end{array}\right.$,则f[f(-1)]=( )
| A. | 0 | B. | 3 | C. | 4 | D. | -1 |
20.设函数f(x)=x2-4x+2在区间[1,4]上的值域为( )
| A. | [-1,2] | B. | (-∞,-1)∪(2,+∞) | C. | (-2,2) | D. | [-2,2] |
19.下列函数中,在区间(0,2)上为增函数的是( )
| A. | y=3-x | B. | y=x2+1 | C. | y=$\frac{1}{x}$ | D. | y=-x2+1 |
18.下列可作为函数y=f(x)的图象的是( )
| A. | B. | C. | D. |
17.已知集合U={1,2,3,4,5,6},M={2,3,5},N={4,6},则(∁UM)∩N=( )
| A. | {4,6} | B. | {1,4,6} | C. | ∅ | D. | {2,3,4,5,6} |
13.命题“?x∈R,x2+2x-1<0”的否定是( )
| A. | ?x∈R,x2+2x-1≥0 | B. | ?x∈R,x2+2x-1<0 | C. | ?x∈R,x2+2x-1≥0 | D. | ?x∈R,x2+2x-1>0 |
12.已知函数f(x)=$\left\{\begin{array}{l}{|lo{g}_{2}x|,0<x<2}\\{\frac{1}{3}{x}^{2}-\frac{8}{3}x+5,x≥2}\end{array}\right.$,若存在实数a,b,c,d,满足f(a)=f(b)=f(c)=f(d),其中0<a<b<c<d,则abcd的取值范围是( )
0 233597 233605 233611 233615 233621 233623 233627 233633 233635 233641 233647 233651 233653 233657 233663 233665 233671 233675 233677 233681 233683 233687 233689 233691 233692 233693 233695 233696 233697 233699 233701 233705 233707 233711 233713 233717 233723 233725 233731 233735 233737 233741 233747 233753 233755 233761 233765 233767 233773 233777 233783 233791 266669
| A. | (8,24) | B. | (10,18) | C. | (12,18) | D. | (12,15) |