鹤壁高中 蔡凤敏 2016.11.042122xPBFxpAFpxy22pxy2-221-2-2xPBFxpAFcos1cos1pBFpAFcos-1cos1pBFpAFPBFAF211.),(),(2211的倾斜角是直线的一条弦，设是抛物线过焦点已知AByxByxAFAB2122yPBFypAFsin1sin1pBFpAFsin-1sin1pBFpAFPBFAF21121-2-2yPBFypAFpyx22pyx2-2pyx2-2)(21yypAB2cos2 pAB)(-21yypAB2cos2 pAB)1(22kpAB)1(22kpABpyx222212214pyypxxpxy22pxy2-22212214pyypxxpyx2-24221221pyypxx4221221pyypxxpyx22pyx22pyx2-2cos22PSOABcos22PSOAB
