- Source: Semidiameter
In geometry, the semidiameter or semi-diameter of a set of points may be one half of its diameter; or, sometimes, one half of its extent along a particular direction.
Special cases
The semi-diameter of a sphere, circle, or interval is the same thing as its radius — namely, any line segment from the center to its boundary.
The semi-diameters of a non-circular ellipse are the halves of its extents along the two axes of symmetry. They are the parameters a, b of the implicit equation
(
x
a
)
2
+
(
y
b
)
2
=
1.
{\displaystyle \left({\frac {x}{a}}\right)^{2}+\left({\frac {y}{b}}\right)^{2}=1.\,\!}
Likewise, the semi-diameters of an ellipsoid are the parameters a, b, and c of its implicit equation
(
x
a
)
2
+
(
y
b
)
2
+
(
z
c
)
2
=
1.
{\displaystyle \left({\frac {x}{a}}\right)^{2}+\left({\frac {y}{b}}\right)^{2}+\left({\frac {z}{c}}\right)^{2}=1.\,\!}
The semi-diameters of a superellipse, superellipsoid, or superquadric can be identified in the same way.
See also
Flattening
Semi-major and semi-minor axes
Semiperimeter
Kata Kunci Pencarian:
- Modul Vitruvian
- Semidiameter
- Vitruvian module
- Semi-major and semi-minor axes
- Diameter
- Lunar distance (navigation)
- Radius
- Equinox
- Semiperimeter
- Pi
- Backstaff
