18.若存在过点O(0,0)的直线l与曲线f(x)=x3-3x2+2x和y=x2+a都相切,则a的值是( )
| A. | 1 | B. | $\frac{1}{64}$ | C. | 1或$\frac{1}{64}$ | D. | 1或-$\frac{1}{64}$ |
11.已知f(x)=Asin(ωx+φ)(A>0,ω>0,|φ|≤$\frac{π}{2}$)是定义域为R的奇函数,且当x=2时,f(x)取得最大值2,则f(1)+f(2)+f(3)+…+f(100)=( )
| A. | 2+2$\sqrt{2}$ | B. | 2-2$\sqrt{2}$ | C. | 2±2$\sqrt{2}$ | D. | 0 |
9.已知非常数列且各项为正数等比数列{an}中,则( )
0 249925 249933 249939 249943 249949 249951 249955 249961 249963 249969 249975 249979 249981 249985 249991 249993 249999 250003 250005 250009 250011 250015 250017 250019 250020 250021 250023 250024 250025 250027 250029 250033 250035 250039 250041 250045 250051 250053 250059 250063 250065 250069 250075 250081 250083 250089 250093 250095 250101 250105 250111 250119 266669
| A. | a1+a2014>a1007+a1008 | B. | a1+a2014<a1007+a1008 | ||
| C. | a1+a2014≥a1007+a1008 | D. | a1+a2014与a1007+a1008无法比较 |