Disk (mathematics)

From Wikipedia, the free encyclopedia

(Redirected from Open disc)
Jump to: navigation, search
A disk is the region bounded by a circle. An open disk is the interior of the disk excluding the bounding circle, while a closed disk (see closed set) is the open disk together with the bounding circle.
A disk is the region bounded by a circle. An open disk is the interior of the disk excluding the bounding circle, while a closed disk (see closed set) is the open disk together with the bounding circle.

In geometry, a disk (also spelt disc) is the region in a plane bounded by a circle.

A disk is said to be closed or open according to whether or not it contains the circle that constitutes its boundary. In Cartesian coordinates, the open disk of center (a,b) and radius R is given by the formula

D=\{(x, y)\in {\mathbb R^2}: (x-a)^2+(y-b)^2 < R^2\}

while the closed disk of the same center and radius is given by

\overline{ D }=\{(x, y)\in {\mathbb R^2}: (x-a)^2+(y-b)^2 \le R^2\}.

The area of a closed or open disk of radius R is πR2 (see π).

The ball is the disk generalised to metric spaces. However, sometimes "disk" is used to mean "ball".

In theoretical physics a disk is a rigid body which is capable of participating in collisions in a two-dimensional gas. Usually the disk is considered rigid so that collisions are deemed elastic.

Retrieved from "http://en.wikipedia.org/wiki/Disk_%28mathematics%29"
Advanced Search
Included Web Search Engines


Safe Search

close

Top Matching Results

Occasionally Search.com will highlight specialized results that are based on the context of your query. Examples of specialized results include specific links to news, images, or video.

Top Matching Results may highlight information from other Search.com pages, content from the CNET Network of sites, or third party content. The listings are based purely on relevance. Search.com does not receive payment for listings in this section but our partners that provide this data may get paid for listing these products.

Sponsored Links

This section contains paid listings which have been purchased by companies that want to have their sites appear for specific search terms and related content. These listings are administered, sorted and maintained by a third party and are not endorsed by Search.com.

Search Results

Search.com sends your search query to several search engines at one time and integrates the results into one list which has been sorted by relevance using Search.com's proprietary algorithm. You can customize the list of search engines included in your metasearch from the preferences.

The search engines that are used in your metasearch may allow companies to pay to have their Web sites included within the results. To view the Paid Inclusion policy for a specific search engine, please visit their Web site. Search.com does not accept payment or share revenue with any search engine partner for listings in this section.