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  2. Parametric surface - Wikipedia

    en.wikipedia.org/wiki/Parametric_surface

    The tangent plane at a regular point is the affine plane in R 3 spanned by these vectors and passing through the point r(u, v) on the surface determined by the parameters. Any tangent vector can be uniquely decomposed into a linear combination of r u {\displaystyle \mathbf {r} _{u}} and r v . {\displaystyle \mathbf {r} _{v}.}

  3. Implicit surface - Wikipedia

    en.wikipedia.org/wiki/Implicit_surface

    This theorem is the key to the computation of essential geometric features of a surface: tangent planes, surface normals, curvatures (see below). But they have an essential drawback: their visualization is difficult. If (,,) is polynomial in x, y and z, the surface is called algebraic. Example 5 is non-algebraic.

  4. Tangent - Wikipedia

    en.wikipedia.org/wiki/Tangent

    The tangent plane to a surface at a given point p is defined in an analogous way to the tangent line in the case of curves. It is the best approximation of the surface by a plane at p , and can be obtained as the limiting position of the planes passing through 3 distinct points on the surface close to p as these points converge to p .

  5. Intersection number - Wikipedia

    en.wikipedia.org/wiki/Intersection_number

    The complexity enters when calculating intersections at points of tangency, and intersections which are not just points, but have higher dimension. For example, if a plane is tangent to a surface along a line, the intersection number along the line should be at least two. These questions are discussed systematically in intersection theory.

  6. Tangent vector - Wikipedia

    en.wikipedia.org/wiki/Tangent_vector

    In mathematics, a tangent vector is a vector that is tangent to a curve or surface at a given point. Tangent vectors are described in the differential geometry of curves in the context of curves in R n. More generally, tangent vectors are elements of a tangent space of a differentiable manifold. Tangent vectors can also be described in terms of ...

  7. Curvature - Wikipedia

    en.wikipedia.org/wiki/Curvature

    An encapsulation of surface curvature can be found in the shape operator, S, which is a self-adjoint linear operator from the tangent plane to itself (specifically, the differential of the Gauss map). For a surface with tangent vectors X and normal N, the shape operator can be expressed compactly in index summation notation as

  8. Surface (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Surface_(mathematics)

    A sphere is the surface of a solid ball, here having radius r. In mathematics, a surface is a mathematical model of the common concept of a surface.It is a generalization of a plane, but, unlike a plane, it may be curved; this is analogous to a curve generalizing a straight line.

  9. Envelope (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Envelope_(mathematics)

    Finally we calculate E 3. Every point in the plane has at least one tangent line to γ passing through it, and so region filled by the tangent lines is the whole plane. The boundary E 3 is therefore the empty set. Indeed, consider a point in the plane, say (x 0,y 0). This point lies on a tangent line if and only if there exists a t such that