Rodrigues's Curvature Formula
where
is the unit Normal Vector and 
is one of the two Principal Curvatures.See also Normal Vector, Principal Curvatures- Inverse Matrix
- Inverse Points
- Inverse Quadratic Interpolation
- Inverse Scattering Method
- Inverse Secant
- Inverse Semigroup
- Inverse Sine
- Inverse Tangent
- Inverse Trigonometric Functions
- Inversion
- Inversion Center
- Inversion Circle
- Inversion Operation
- Inversion Radius
- Inversive Distance
- Inversive Geometry
- Inverted Funnel
- Inverted Snub Dodecadodecahedron
- Invertible Knot
- Involuntary
- Involute
- Involution (Group)
- Involution (Line)
- Involution (Operator)
- Involution (Set)