動どう径けい

noun

radius vector

In mathematics, a vector from a fixed origin to a point, especially in polar coordinates or celestial mechanics.

• 極きょく座ざ標ひょうでは、点てんの位い置ちは動どう径けいと偏へん角かくで表あらわされる。

  In polar coordinates, the position of a point is expressed by the radius vector and the polar angle.