讲《圆锥曲线》试卷二评1925:1722yx三、解答题2max2)2(,42)1(:18pSpap182)2(,5)1(:1922yxe)2)(23()2(,1)1(:20xym12)2(,36)1(:21exyONM0)22(22axpax代入抛物线得:04)22(22apa224811||papABAB:18axyl:1)设直线解:(2pap24pa42pap综上得),()2(00 yxAB的中点坐标为设paxypaxxx00210,2则)(:paxpyAB的中垂线方程为)0,2(paNxyONM2222224811||pappapAB=又AB:18),()2(00 yxAB的中点坐标为设)0,2(paNpapadABN22|2|的距离为到直线ppapS2222212 )42(,222pappapp2max24pSpa时,当)(:paxpyAB的中垂线方程为:19y
F2F1OxPaPFPFPFPF2||||||2||12121且)解:( aPFaPF2||,4||2121PFPF 又222222214416,4||||caacPFPF即522ace1P2Pxyabe2,45)2(22渐近线为知:由离心率),(),2,(),2,(00222111yxPxxPxxP设494272121xxOPOP由0221 PPPP由3)2(2322121xxyxxx:19y
F2F1OxP1P2P494272121xxOPOP由0221 PPPP由3)2(23221