Topic summary
Signed curvature
Extracted from the Wikipedia article Curvature.
Signed curvature
For plane curves, it can be useful to express the curvature as a single scalar that can be positive or negative, called the signed curvature or oriented curvature and denoted with a lowercase k. The signed curvature formulas are similar to those for κ except that they omit taking the absolute value of the numerator: