[[단위접벡터,unit_tangent_vector]] $\vec{T}$
[[단위법선벡터,unit_normal_vector]] $\vec{N}$
[[단위이중법선벡터,unit_binormal_vector]] $\vec{B}$

[[곡률,curvature]] $\kappa$

$\vec{T}=\frac{d\vec{r}}{ds}$
$\vec{N}=\frac1{\kappa} \frac{d\vec{T}}{ds}$
$\vec{B}=\vec{T}\times\vec{N}$

셋의 관계는
$\begin{align}\frac{d\vec{T}}{ds}&=&\kappa\vec{N}&\\\frac{d\vec{N}}{ds}&=-\kappa\vec{T}&&+\tau\vec{B}\\\frac{d\vec{B}}{ds}&=&-\tau\vec{N}&\end{align}$

(via [https://suhak.tistory.com/922])

위의 식을 [[반대칭행렬,skew-symmetric_matrix]]로 나타내면 TBW

MKLINK
[[곡선,curve#s-1]]
자연방정식 natural_equation or 본질방정식 intrinsic_equation
[[torsion]]
[[곡률,curvature]] $\kappa$

----
pagename: 이건 임시. Prefix는 Frenet, Frenet-Serret, TNB... suffix는 _formula, _frame, ([[틀,frame]]), equations ... TBD.
 [[프레네_틀,Frenet_frame]] and [[프레네-세레_공식,Frenet-Serret_formula]]?

https://ko.wikipedia.org/wiki/프레네-세레_공식
https://en.wikipedia.org/wiki/Frenet–Serret_formulas
[[https://terms.naver.com/entry.naver?docId=6512707&cid=60207&categoryId=60207 수학백과: 프레네 공식]]