Definition:Radius
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Disambiguation
This page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.
Radius may refer to:
- Geometry:
- Radius of a Circle: a straight line segment whose endpoints are the center and the circumference of the circle.
- Radius of a Sphere: a straight line segment whose endpoints are the center and the surface of the sphere.
- Analytic Geometry:
- The radial coordinate of a point $P$ in a system of polar coordinates is also known as the radius of $P$.
- Topology and Metric Spaces:
- Radius of an $\epsilon$-Ball: In the open $\epsilon$-ball $B_\epsilon \left({x}\right)$ of the point $x$, the value $\epsilon$ is its radius.
- Analysis:
- Radius of Convergence: The distance from the endpoints to the midpoint of the interval on which a power series is convergent.
Linguistic Note
The plural of radius is radii, pronounced ray-dee-eye.
This irregular plural form stems from the Latin origin of the word radius, meaning ray.
The ugly incorrect form radiuses can apparently be found, but rarely in a mathematical context.
Internationalization
Radius is translated:
In French: | rayon |