(3’+5’+8’)設(shè)P(a,b)(b≠0)是平面直角坐標(biāo)系xOy中的點(diǎn),l是經(jīng)過原點(diǎn)與點(diǎn)(1,b)的直線,記Q是直線l與拋物線x2=2py(p≠0)的異于原點(diǎn)的交點(diǎn)
(1)若a=1,b=2,p=2,求點(diǎn)Q的坐標(biāo);
(2)若點(diǎn)P(a,b)(ab≠0)在橢圓+y2=1上,p=,
求證:點(diǎn)Q落在雙曲線4x2-4y2=1上;
(3)若動(dòng)點(diǎn)P(a,b)滿足ab≠0,p=,若點(diǎn)Q始終落在一條關(guān)于x軸對稱的拋物線上,試問動(dòng)點(diǎn)P的軌跡落在哪種二次曲線上,并說明理由.