题目内容
抛物线x2=y的准线方程为
A.x=-1 B.y=-1 C.x= D.y=
D
(A)4x+1=0 (B)4y+1=0 (C)2x+1=0 (D)2y+1=0
A.4x+1=0 B.4y+1=0 C.2x+1=0 D.2y+1=0