Cusp
A cusp is a point on a continuous curve where the tangent vector reverses sign as the curve is traversed. A function 
has a cusp (also called a Spinode) at a point 
if is Continuous at and
from one side while 
from the other side, so the curve is Continuous but the Derivative is not. A cusp is atype of Double Point. The above plot shows the curve 
, which has a cusp at the Origin.
References
Walker, R. J. Algebraic Curves. New York: Springer-Verlag, pp. 57-58, 1978.
- Cramér Conjecture
- Cramér-Euler Paradox
- Cramér's Theorem
- Craps
- CRC
- Creative Telescoping
- Cremona Transformation
- Cribbage
- Criss-Cross Method
- Criterion
- Critical Line
- Critical Point
- Critical Strip
- Crook
- Crookedness
- Cross
- Cross-Cap
- Cross-Correlation
- Cross-Correlation Coefficient
- Cross-Correlation Theorem
- Cross Curve
- Crossed Ladders Problem
- Crossed Trough
- Cross Fractal
- Crossing Number (Graph)