## Semi-major and semi-minor axes |

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In **semi-major axis** is one half of the major axis, and thus runs from the centre, through a

The length of the semi-major axis of an ellipse is related to the semi-minor axis's length through the

The semi-major axis of a

A

The *semi-minor axis* of an ellipse or hyperbola is a line segment that is at

The major and minor axes are the

The equation of an ellipse is:

Where (h,k) is the center of the ellipse in

The semi-major axis is the mean value of the maximum and minimum distances and of the ellipse from a focus — that is, of the distances from a focus to the endpoints of the major axis. In astronomy these extreme points are called

The semi-minor axis of an ellipse is the

The

- so .

Now consider the equation in

The mean value of and , for and is

In an ellipse, the semi-major axis is the

The semi-minor axis of an ellipse runs from the center of the ellipse (a point halfway between and on the line running between the

The semi-minor axis is related to the semi-major axis through the eccentricity and the

A

The length of the semi-minor axis could also be found using the following formula,^{[1]}

where is the distance between the foci, and are the distances from each focus to any point in the ellipse.

Other Languages

العربية: نصف المحور الرئيسي

asturianu: Semiexe mayor

বাংলা: পরাক্ষ

Bân-lâm-gú: Kúi-tō tn̂g pòaⁿ-kèng

беларуская: Вялікая паўвось

български: Голяма полуос

català: Semieix major

čeština: Velká poloosa dráhy

Deutsch: Große Halbachse

Ελληνικά: Ημιμεγάλος Άξονας

español: Semieje mayor

Esperanto: Granda duonakso

euskara: Ardatzerdi handi

فارسی: نیمقطر بزرگ

français: Grand axe

Gaeilge: Ais leathmhór

galego: Semieixo maior

한국어: 긴반지름

հայերեն: Մեծ կիսաառանցք

हिन्दी: अर्ध दीर्घ अक्ष

Bahasa Indonesia: Sumbu semi-mayor

italiano: Semiasse maggiore

ქართული: დიდი ნახევარღერძი

Latina: Semiaxis maior

latviešu: Orbītas lielā pusass

magyar: Fél nagytengely

македонски: Голема полуоска

मराठी: अर्धदीर्घ अक्ष

Bahasa Melayu: Paksi semimajor

日本語: 軌道長半径

norsk: Store halvakse

norsk nynorsk: Stor halvakse

occitan: Semiaxe major

polski: Półoś wielka

português: Semieixo maior

română: Semiaxa mare

русский: Большая полуось

සිංහල: අඩ-මහා අක්ෂය

Simple English: Semi-major axis

slovenčina: Veľká polos

српски / srpski: Велика полуоса

srpskohrvatski / српскохрватски: Velika poluosa

suomi: Radan isoakselin puolikas

svenska: Halv storaxel

தமிழ்: அரைப்பேரச்சு

ไทย: กึ่งแกนเอก

Türkçe: Ana eksen

українська: Велика піввісь

Tiếng Việt: Bán trục lớn

中文: 半長軸