1·The pity is that the first auxiliary directrix after modification is generally expressed in an algebraic form, because of the complexity of the vectorial expression.
遗憾的是，由于其矩阵表达式有些复杂，一般都将修改后的第一辅助准线表示为代数形式。
2·The directrix line of a conic.
二次曲线的准线。