14.已知函数f(x)=aln(x+1)-x2在区间(0,1)内任取两个实数p,q,且p≠q,不等式$\frac{f(p+1)-f(q+1)}{p-q}$>2恒成立,则实数a的取值范围为( )
| A. | (12,30] | B. | (-∞,18] | C. | [18,+∞) | D. | (-12,18] |
10.函数f(x)为奇函数,且图象关于x=1对称,当x∈(0,1)时,f(x)=ln(x+1),则当x∈(3,4)时,f(x)为( )
| A. | 增函数且f(x)>0 | B. | 增函数且f(x)<0 | C. | 减函数且f(x)>0 | D. | 减函数且f(x)<0 |
7.集合A={x|lnx≥0},B={x|x2≤9},则A∩B=( )
0 233841 233849 233855 233859 233865 233867 233871 233877 233879 233885 233891 233895 233897 233901 233907 233909 233915 233919 233921 233925 233927 233931 233933 233935 233936 233937 233939 233940 233941 233943 233945 233949 233951 233955 233957 233961 233967 233969 233975 233979 233981 233985 233991 233997 233999 234005 234009 234011 234017 234021 234027 234035 266669
| A. | (1,3) | B. | [1,3] | C. | [1,+∞] | D. | [e,3] |