题目

The sun ___ in the east and___ in the west. A. raises; set B. rise; sets C. rises; sets D. rises; set 答案：C设函数f（x）=alnx-bx2，a，b∈R．（Ⅰ）若曲线f（x）在点（1，f（1））处的切线方程为y=-12，求实数a，b的值；（Ⅱ）若b=1，求函数f（x）的最大值．