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  2. Tennis racket theorem - Wikipedia

    en.wikipedia.org/wiki/Tennis_racket_theorem

    The tennis racket theorem or intermediate axis theorem, is a kinetic phenomenon of classical mechanics which describes the movement of a rigid body with three distinct principal moments of inertia. It has also been dubbed the Dzhanibekov effect , after Soviet cosmonaut Vladimir Dzhanibekov , who noticed one of the theorem's logical consequences ...

  3. Vladimir Dzhanibekov - Wikipedia

    en.wikipedia.org/wiki/Vladimir_Dzhanibekov

    In 1985 he demonstrated stable and unstable rotation of a T-handle nut from the orbit, subsequently named the Dzhanibekov effect. The effect had been long known from the tennis racket theorem, which says that rotation about an object's intermediate principal axis is unstable while in free fall. In 1985 he was promoted to the rank of major ...

  4. Poinsot's ellipsoid - Wikipedia

    en.wikipedia.org/wiki/Poinsot's_ellipsoid

    As described in the tennis racket theorem, rotation of an object around its first or third principal axis is stable, while rotation around its second principal axis (or intermediate axis) is not. The motion is simplified in the case of an axisymmetric body, in which the moment of inertia is the same about two of the principal axes.

  5. Surface equivalence principle - Wikipedia

    en.wikipedia.org/wiki/Surface_equivalence_principle

    The principle yields an equivalent problem for a radiation problem by introducing an imaginary closed surface and fictitious surface current densities.It is an extension of Huygens–Fresnel principle, which describes each point on a wavefront as a spherical wave source.

  6. Hockey-stick identity - Wikipedia

    en.wikipedia.org/wiki/Hockey-stick_identity

    Download as PDF; Printable version; In other projects ... Fermat's identity or Chu's Theorem, [3] ... by the partial sum formula for geometric series, ...

  7. Marchenko–Pastur distribution - Wikipedia

    en.wikipedia.org/wiki/Marchenko–Pastur...

    The theorem is named after Soviet Ukrainian mathematicians Volodymyr Marchenko and Leonid Pastur who proved this result in 1967. If X {\displaystyle X} denotes a m × n {\displaystyle m\times n} random matrix whose entries are independent identically distributed random variables with mean 0 and variance σ 2 < ∞ {\displaystyle \sigma ^{2 ...

  8. Bessel function - Wikipedia

    en.wikipedia.org/wiki/Bessel_function

    Bessel functions describe the radial part of vibrations of a circular membrane.. Bessel functions, first defined by the mathematician Daniel Bernoulli and then generalized by Friedrich Bessel, are canonical solutions y(x) of Bessel's differential equation + + = for an arbitrary complex number, which represents the order of the Bessel function.

  9. Gauss–Codazzi equations - Wikipedia

    en.wikipedia.org/wiki/Gauss–Codazzi_equations

    In Riemannian geometry and pseudo-Riemannian geometry, the Gauss–Codazzi equations (also called the Gauss–Codazzi–Weingarten-Mainardi equations or Gauss–Peterson–Codazzi formulas [1]) are fundamental formulas that link together the induced metric and second fundamental form of a submanifold of (or immersion into) a Riemannian or pseudo-Riemannian manifold.