14.已知f1(x)=(x2+2x+1)ex,f2(x)=[f1(x)]′,f3(x)=[f2(x)]′,…,fn+1(x)=[fn(x)]′,n∈N*.设fn(x)=(anx2+bnx+cn)ex,则b2015=( )
| A. | 4034 | B. | 4032 | C. | 4030 | D. | 4028 |
13.正方体ABCD-A1B1C1D1的棱长为6,O1为正方形A1B1C1D1的中心,则四棱锥O1-ABCD的外接球的表面积为( )
| A. | 9π | B. | 324π | C. | 81π | D. | $\frac{243}{2}π$ |
12.已知函数f(x)为偶函数且满足:f(x)=f(4-x),当x∈[0,2]时,f(x)=x-1,则不等式xf(x)>0在[-1,3]上的解集为( )
| A. | (1,3) | B. | (-1,1) | C. | (-1,0)∪(1,3) | D. | (-1,0)∪(0,1) |
10.已知$sin(α+\frac{π}{4})=-\frac{1}{3}$,则$cos(α-\frac{π}{4})$的值为( )
| A. | $-\frac{1}{3}$ | B. | $\frac{1}{3}$ | C. | $\frac{2\sqrt{2}}{3}$ | D. | -$\frac{2\sqrt{2}}{3}$ |
7.下列函数中,在区间(0,1)上单调递增的有( )
①f(x)=x3-2x;②f(x)=$\frac{ln|x|}{{x}^{2}}$;③f(x)=-2x2+4|x|+3.
0 233607 233615 233621 233625 233631 233633 233637 233643 233645 233651 233657 233661 233663 233667 233673 233675 233681 233685 233687 233691 233693 233697 233699 233701 233702 233703 233705 233706 233707 233709 233711 233715 233717 233721 233723 233727 233733 233735 233741 233745 233747 233751 233757 233763 233765 233771 233775 233777 233783 233787 233793 233801 266669
①f(x)=x3-2x;②f(x)=$\frac{ln|x|}{{x}^{2}}$;③f(x)=-2x2+4|x|+3.
| A. | 0个 | B. | 1个 | C. | 2个 | D. | 3个 |