12点

「$${12}$$点」

半径$${2}$$の円球面上の$${12}$$点

$${N\quad(0,0,2)}$$

$${An\quad(0,\sqrt{3},1)}$$
$${Bn\quad(\frac{2\sqrt{2}}{\sqrt{3}},\frac{1}{\sqrt{3}},1)}$$
$${Cn\quad(1,-\sqrt{2},1)}$$
$${Dn\quad(-1,-\sqrt{2},1)}$$
$${En\quad(-\frac{2\sqrt{2}}{\sqrt{3}},\frac{1}{\sqrt{3}},1)}$$

$${As\quad(0,\sqrt{3},-1)}$$
$${Bs\quad(\frac{2\sqrt{2}}{\sqrt{3}},\frac{1}{\sqrt{3}},-1)}$$
$${Cs\quad(1,-\sqrt{2},-1)}$$
$${Ds\quad(-1,-\sqrt{2},-1)}$$
$${Es\quad(-\frac{2\sqrt{2}}{\sqrt{3}},\frac{1}{\sqrt{3}},-1)}$$

$${S\quad(0,0,-2)}$$

$${X^2+Y^2=(\sqrt{3})^2}$$
$${X^2+Y^2+Z^2=2^2}$$

$${cf.}$$
$${「5点+」}$$

$${「正25辺体」}$$