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如果抛物线y2=a(x+1)的准线方程是x=-3,那么这条抛物线的焦点坐标是( ...
如果抛物线y2=a(x+1)的准线方程是x=-3,那么这条抛物线的焦点坐标是( )
A.(3,0)
B.(2,0)
C.(1,0)
D.(-1,0)
考点分析:
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