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  2. Descartes' theorem - Wikipedia

    en.wikipedia.org/wiki/Descartes'_theorem

    When they are tangent, they form a quadruple of tangent circles with the -axis and with the circle for their mediant (+) / (+). [ 35 ] The Ford circles belong to a special Apollonian gasket with root quadruple ( 0 , 0 , 1 , 1 ) {\displaystyle (0,0,1,1)} , bounded between two parallel lines, which may be taken as the x {\displaystyle x} -axis ...

  3. Cylindrical coordinate system - Wikipedia

    en.wikipedia.org/wiki/Cylindrical_coordinate_system

    Cylindrical coordinate system. A cylindrical coordinate system with origin O, polar axis A, and longitudinal axis L. The dot is the point with radial distance ρ = 4, angular coordinate φ = 130°, and height z = 4. A cylindrical coordinate system is a three-dimensional coordinate system that specifies point positions by the distance from a ...

  4. Brewster's angle - Wikipedia

    en.wikipedia.org/wiki/Brewster's_angle

    For a glass medium (n2 ≈ 1.5) in air (n1 ≈ 1), Brewster's angle for visible light is approximately 56°, while for an air-water interface (n2 ≈ 1.33), it is approximately 53°. Since the refractive index for a given medium changes depending on the wavelength of light, Brewster's angle will also vary with wavelength.

  5. Mathematics of three-phase electric power - Wikipedia

    en.wikipedia.org/wiki/Mathematics_of_three-phase...

    Mathematics and basic principles of three-phase electric power. One voltage cycle of a three-phase system, labeled 0 to 360° (2π radians) along the time axis. The plotted line represents the variation of instantaneous voltage (or current) with respect to time. This cycle repeats with a frequency that depends on the power system.

  6. Logarithm - Wikipedia

    en.wikipedia.org/wiki/Logarithm

    The inverse of addition is subtraction, and the inverse of multiplication is division. Similarly, a logarithm is the inverse operation of exponentiation . Exponentiation is when a number b , the base , is raised to a certain power y , the exponent , to give a value x ; this is denoted b y = x . {\displaystyle b^{y}=x.}

  7. Pearson correlation coefficient - Wikipedia

    en.wikipedia.org/wiki/Pearson_correlation...

    The p-value for the permutation test is the proportion of the r values generated in step (2) that are larger than the Pearson correlation coefficient that was calculated from the original data. Here "larger" can mean either that the value is larger in magnitude, or larger in signed value, depending on whether a two-sided or one-sided test is ...

  8. Median - Wikipedia

    en.wikipedia.org/wiki/Median

    Median. Calculating the median in data sets of odd (above) and even (below) observations. The median of a set of numbers is the value separating the higher half from the lower half of a data sample, a population, or a probability distribution. For a data set, it may be thought of as the “middle" value. The basic feature of the median in ...