point of tangency
61Hairy ball theorem — The hairy ball theorem of algebraic topology states that there is no nonvanishing continuous tangent vector field on the sphere. If f is a continuous function that assigns a vector in R3 to every point p on a sphere such that f ( p ) is always… …
62Marginal product of labor — In economics, the marginal product of labor also known as MPL or MPN is the change in output from hiring one additional unit of labor. It is the increase in output added by the last unit of labor.[1] Ceteris paribus that no other inputs to… …
63Bézout's theorem — is a statement in algebraic geometry concerning the number of common points, or intersection points, of two plane algebraic curves. The theorem claims that the number of common points of two such curves X and Y is equal to the product of their… …
64Osculating orbit — In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space (at a given moment of time) is the gravitational Kepler orbit (i.e. ellipse or other conic) that it would have about its central body (corresponding to… …
65Focal surface — For a surface in three dimension the focal surface, surface of centers or evolute is formed by taking the centers of the curvature spheres, which are the tangential spheres whose radii are the reciprocals of one of the principal curvatures at the …
66tangent line — In geometry, a line that intersects a circle exactly once; in calculus, a line that touches a curve at one point and whose slope is equal to that of the curve at that point. Particularly useful as approximations of curves in the immediate… …
67Deltoid curve — The red curve is a deltoid. In geometry, a deltoid, also known as a tricuspoid or Steiner curve, is a hypocycloid of three cusps. In other words, it is the roulette created by a point on the circumference of a circle as it rolls without slipping… …
68stereographic projection — Perspective projections in which a graticule of reduced earth is projected onto a plane tangential to reduced earth at a point from a point diametrically opposite to the point of tangency. In such a projection, the meridians and parallels are… …
69osculating circle — noun the circle that touches a curve (on the concave side) and whose radius is the radius of curvature • Syn: ↑circle of curvature • Hypernyms: ↑circle * * * noun : a circle which is tangent to a curve at a given point, which lies in the limiting …
70Tractrix — (from the Latin verb trahere pull, drag ), or tractrice, is the curve along which a small object moves, under the influence of friction, when pulled on a horizontal plane by a piece of thread and a puller that moves at a right angle to the… …
