A:were expecting going
B:is expected to go
C:was expecting going
D:are expected to go
下列实验操作正确的是( )
设函数f(x)=ax2+bx+c且f(1)=﹣a2,3a>2c>2b.
(1)试用反证法证明:a>0
(2)证明:﹣3<ba<-34.