The 漸伸線 of the 星形線 is a hypocycloid involute for 
. Surprisingly, it is another 星形線 scaled by a factor 
and rotated 
of a turn. For an 星形線 with parametric equations
 |  |  |
(1)
|
 |  |  |
(2)
|
 |  | ![1/8[3cost-cos(3t)]](/images/equations/AstroidInvolute/Inline12.svg) |
(3)
|
 |  | ![1/8[3sint+sin(3t)].](/images/equations/AstroidInvolute/Inline15.svg) |
(4)
|
星形線的漸伸線
參見
星形線, 星形線漸屈線, 漸伸線使用 探索
引用為
Weisstein, Eric W. “星形線的漸伸線。” 來自 —— 資源。 https://mathworld.tw/AstroidInvolute.html