利用共焦点二次曲线束的理论，得出了二次曲线的焦点的一种十分方便的直接算法，并给出了一个计算实例。

By using the theory of common focus conic bundle, a kind of advantageous directness arithmetic about conic's focus is obtained, and an example is given.

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通货膨胀率和失业率之间关系，是 菲利普斯 曲线描述 的基本内容，也是经济学争论 的焦点之一。

The relation between inflation and employment rate, is expressed by Phillips Curve, and also is one of the focuses of debates of economics.

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解析几何中圆锥截线的一条封闭曲线，包含了与两个定点(焦点)之距离呈等值增加的所有点。

Closed curve, one of the conic sections of analytic geometry, consisting of all points whose distances from each of two fixed points (foci) add up to the same value.

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