Isoptic Curve
For a given curve 
, consider the locus of the point 
from where the Tangents from to meet at a fixedgiven Angle. This is called an isoptic curve of the given curve.
| Curve | Isoptic |
| Cycloid | curtate or prolate Cycloid |
| Epicycloid | Epitrochoid |
| Hypocycloid | Hypotrochoid |
| Parabola | Hyperbola |
| Sinusoidal Spiral | Sinusoidal Spiral |
References
Lawrence, J. D. A Catalog of Special Plane Curves. New York: Dover, pp. 58-59 and 206, 1972. Yates, R. C. ``Isoptic Curves.'' A Handbook on Curves and Their Properties. Ann Arbor, MI: J. W. Edwards, pp. 138-140, 1952.
- Nash's Theorem
- Nasik Square
- Nasty Knot
- Natural Density
- Natural Equation
- Natural Independence Phenomenon
- Natural Invariant
- Natural Logarithm
- Natural Measure
- Natural Norm
- Natural Number
- Naught
- Navigation Problem
- N-Cluster
- n-Cube
- Nearest Integer Function
- Nearest Neighbor Problem
- Near-Integer
- Near Noble Number
- Near-Pencil
- Necessary
- Necker Cube
- Necklace
- Needle
- Negation