A:measured,i
B:measured,to
C:measured,for
D:measured,at
字母抄写。
①Kk
____
②Ll
③Mm
④Nn
(Ⅰ)讨论函数f(x)的极值;
(Ⅱ)当x≥0时,ex≥ax2+x+1,求a的取值范围.