Orthoptic Curve

An Isoptic Curve formed from the locus of Tangents meeting at Right Angles.The orthoptic of a Parabola is its Directrix. The orthoptic of a centralConic was investigated by Monge and is a Circle concentric with the Conic Section. Theorthoptic of an Astroid is a Circle.

Lawrence, J. D. A Catalog of Special Plane Curves. New York: Dover, pp. 58 and 207, 1972.

• Pong Hau K'i
• Pons Asinorum
• Pontryagin Class
• Pontryagin Duality
• Pontryagin Maximum Principle
• Pontryagin Number
• Ponzo's Illusion
• Pop
• Population Comparison
• Population Growth
• Porism
• Porter's Constant
• Poset
• Poset Dimension
• Position Four-Vector
• Position Vector
• Positive
• Positive Definite Function
• Positive Definite Matrix
• Positive Definite Quadratic Form
• Positive Definite Tensor
• Positive Integer
• Positive Semidefinite Matrix
• Positive Semidefinite Quadratic Form
• Postage Stamp Problem