X-Nico

4 unusual facts about multiplicative inverse


Decathlon scoring tables

For field events, this was a straightforward statistical procedure; for track events, the reciprocal of the athlete's time, representing speed, was used as the independent variable.

Interval ratio

Ratios have an inverse relationship to string length, for example stopping a string at two-thirds (2:3) its length produces a pitch one and one-half (3:2) that of the open string (not to be confused with Inversion (music)).

Moritz Ludwig Frankenheim

By 1826, he was already using the integer reciprocals of Weiss' coefficients (the intersection of a plane with the three crystallographic axes) to describe the spatial positions of crystal surfaces, from which the British crystallographer William Hallowes Miller (1801-1880) developed the concept of Miller indices in 1839.

Photographic filter

Close-up lenses are usually specified by their optical power, the reciprocal of the focal length in meters.


Backup rotation scheme

One acceptable weight is a constant exponent (possibly the square) of the multiplicative inverse of the duration (possibly expressed in the number of days) between the date of the generation and the generation available before it.

Median absolute deviation

The factor 1.4826\ \approx 1/\left(\Phi^{-1}(3/4)\right) results from the reciprocal of the normal inverse cumulative distribution function, \Phi^{-1}(P), evaluated at probability P=3/4.


see also

Semifield

In ring theory, combinatorics, functional analysis, and theoretical computer science, a semifield is a semiring (MSC 16Y60) (S,+,·) in which all elements have a multiplicative inverse.