polar of a point
collocation一点的极线
The polar of a point on a circle is the tangent at that point.
圆上一点的极线就是该点处的切线。
极线
先理解核心含义，再看它在真实句子里的用法。
极线
the line joining the points of contact of tangents drawn from a point (the pole) to a curve
To find the polar of a point outside a circle, draw the two tangents from that point and connect their points of contact.
要求一个圆外一点的极线，可以从该点作两条切线并连接它们的切点。
几何术语：从极点引向曲线的切线的切点连线。
连接从称为极点的点画出的切线与曲线相交的接触点的线。
The line joining the points of contact of tangents drawn to meet a curve from a point called the pole of the line.
In the diagram, the polar of point P is the line through the two points where the tangents touch the ellipse.
在图中，点 P 的极线是经过两条切线与椭圆相切的那两个切点的直线。
Using a ruler, we constructed the polar by joining the two contact points of the tangents drawn from the pole.
我们用直尺连接从极点所作两条切线的两个切点，从而构造出极线。
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一点的极线
The polar of a point on a circle is the tangent at that point.
圆上一点的极线就是该点处的切线。
极点与极线
The pole and polar are dual elements in projective geometry.
极点与极线是射影几何中的对偶元素。
关于圆的极线
If a point lies outside a circle, its polar with respect to the circle is the chord of contact.
若一点位于圆外，它关于圆的极线就是切点弦。
圆锥曲线的所有极线
Each of the polars of a conic has a unique pole in the plane.
圆锥曲线的每条极线在平面内都有唯一的极点。
截然相反的人或事物
My brother is the polar opposite of me.
我哥哥和我截然相反。
Use polar naturally, then get feedback on meaning, tone, grammar, and phrasing.
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polar 是 pole（极点）的形容词；几何里从极点引两条切线，两切点的连线就是极线，记住“极点的线”。
语域：formal 常见场景：数学、几何学 polar（极线）是几何学术语，通常出现在数学教材或专业文献中，多用于正式、学术性的语境；日常英语中较少用到。
真正押韵：solar、molar、roller 都以 /əulə/ 结尾，与 polar 同韵。拼写相似但读音不同：scholar 虽以 -olar 结尾，但读 /ˈskɒlə/，并不与 polar 押韵。
Dictionary facts from ECDICT, WIKTIONARY, WORDNET.