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  2. Riesz function - Wikipedia

    en.wikipedia.org/wiki/Riesz_function

    the terms of which eventually decrease as the inverse fourth power of . The above series are absolutely convergent everywhere, and hence may be differentiated term by term, leading to the following expression for the derivative of the Riesz function:

  3. Two-ray ground-reflection model - Wikipedia

    en.wikipedia.org/wiki/Two-ray_ground-reflection...

    As distance increases, these waves add up constructively and destructively, giving regions of up-fade and down-fade. As the distance increases beyond the critical distance or first Fresnel zone, the power drops proportionally to an inverse of fourth power of . An approximation to critical distance may be obtained by setting Δφ to π as the ...

  4. Inverse iteration - Wikipedia

    en.wikipedia.org/wiki/Inverse_iteration

    In numerical analysis, inverse iteration (also known as the inverse power method) is an iterative eigenvalue algorithm. It allows one to find an approximate eigenvector when an approximation to a corresponding eigenvalue is already known. The method is conceptually similar to the power method. It appears to have originally been developed to ...

  5. Newton's theorem of revolving orbits - Wikipedia

    en.wikipedia.org/wiki/Newton's_theorem_of...

    However, Newton's theorem shows that an inverse-cubic force may be applied to a particle moving under a linear or inverse-square force such that its orbit remains closed, provided that k equals a rational number. (A number is called "rational" if it can be written as a fraction m/n, where m and n are integers.)

  6. Magnetic dipole–dipole interaction - Wikipedia

    en.wikipedia.org/wiki/Magnetic_dipole–dipole...

    Magnetic dipole–dipole interaction, also called dipolar coupling, refers to the direct interaction between two magnetic dipoles.Roughly speaking, the magnetic field of a dipole goes as the inverse cube of the distance, and the force of its magnetic field on another dipole goes as the first derivative of the magnetic field.

  7. Cepstrum - Wikipedia

    en.wikipedia.org/wiki/Cepstrum

    The term cepstrum was derived by reversing the first four letters of spectrum. Operations on cepstra are labelled quefrency analysis (or quefrency alanysis [1]), liftering, or cepstral analysis. It may be pronounced in the two ways given, the second having the advantage of avoiding confusion with kepstrum. Steps in forming cepstrum from time ...

  8. List of mathematical functions - Wikipedia

    en.wikipedia.org/wiki/List_of_mathematical_functions

    Exponential function: raises a fixed number to a variable power. Hyperbolic functions: formally similar to the trigonometric functions. Inverse hyperbolic functions: inverses of the hyperbolic functions, analogous to the inverse circular functions. Logarithms: the inverses of exponential functions; useful to solve equations involving exponentials.

  9. Fourth power - Wikipedia

    en.wikipedia.org/wiki/Fourth_power

    Fermat knew that a fourth power cannot be the sum of two other fourth powers (the n = 4 case of Fermat's Last Theorem; see Fermat's right triangle theorem). Euler conjectured that a fourth power cannot be written as the sum of three fourth powers, but 200 years later, in 1986, this was disproven by Elkies with: 20615673 4 = 18796760 4 ...