A:甲醛
B:MgSO4
C:NH4Cl
D:Hg(NO3)2
Tom
Mary
Jack
Peter
Anna
I have many friends. What are they doing now?
Look!
读我国部分地区略图(如图),完成下列要求
设a∈R若函数y=eax+3x,x∈R有大于零的极值点,则a的取值为( )