 Disk (mathematics)

A planar Euclidean disk consists of the points within a fixed radius of a centre, with either the open or closed boundary convention. The closed disk centered at the origin is $D_R=\{x\in {\mathbb{R}}^2:|x|\le R\}$ and has area $\pi R^2$. It is the two-dimensional closed Euclidean ball; the general closed disc may have any dimension.

In mathematics, particularly in geometry, a "disk" (or "disc") refers to a two-dimensional shape that is defined as the region in the plane that is enclosed by a circle. The term can have slightly different meanings depending on the context: 1. **Closed Disk**: This includes all the points inside a circle as well as the points on the boundary (the circumference of the circle).