问题:
设等差数列{a n}的前n项和为S n,S m -1=-2,S m=0,S m +1=3,则 = ( )
A.3
B.4
C.5
D.6
设等差数列{a n}的前n项和为S n,S m -1=-2,S m=0,S m +1=3,则 = ( )
A.3 |
B.4 |
C.5 |
D.6 |
参考答案: