, the curvature of a surface
at a point
is the value of the second derivative
of the function
describing the surface, at that point. Or, more comprehensibly, if a curve is described
by f(x) (for all x), the curvature at (n, f(n)) is f''(n). This applies to shapes
which aren't just curves
, and to curves
that aren't just defined a two-dimensioanl space.
Practical examples: The curvature of a straight line is 0, the curvature of a circle is a constant.
Compare with radius of curvature.