抛物线x²+8y＝0的焦点坐标是 A(0,2) B(0,-2) C(0,4) D抛物线x²+8y＝0的焦点坐标_数学解答

抛物线x²+8y＝0的焦点坐标是 A(0,2) B(0,-2) C(0,4) D
抛物线x²+8y＝0的焦点坐标是 A(0,2) B(0,-2) C(0,4) D(0,-4)

人气：310 ℃　时间：2020-04-21 16:40:30

解答

X²=-8y
(0,-8/4)=(0,-2)
选B