A unit disk is a disk with radius 1.

The (open) unit disk can also be considered to be the region in the complex plane defined by , where denotes the complex modulus. (The closed unit disk is similarly defined as ).

Removing the origin from the open disk gives the punctured disk . Removing a full radius instead gives a slit disk, for example .

See also

Bounded Symmetric Domain, Five Disks Problem, Lower Half-Disk, Punctured Disk, Semicircle, Slit Disk, Unit Circle, Unit Disk Integral, Unit Square, Upper Half-Disk

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Cite this as:

Weisstein, Eric W. "Unit Disk." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/UnitDisk.html

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