Johan Frederik Steffensen (28 February 1873, in

Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

– 20 December 1961) was a Danish

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

statistician A statistician is a person who works with theoretical or applied statistics. The profession exists in both the private and public sectors. It is common to combine statistical knowledge with expertise in other subjects, and statisticians may wor ...

, and actuary who did research in the fields of calculus of finite differences and

interpolation In the mathematical field of numerical analysis, interpolation is a type of estimation, a method of constructing (finding) new data points based on the range of a discrete set of known data points. In engineering and science, one often has ...

. He was professor of actuarial science at the University of Copenhagen from 1923 to 1943.

Steffensen's inequality Steffensen's inequality is an equation in mathematics named after Johan Frederik Steffensen. It is an integral In mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, ...

and

Steffensen's method In numerical analysis, Steffensen's method is a root-finding technique named after Johan Frederik Steffensen which is similar to Newton's method. Steffensen's method also achieves quadratic convergence, but without using derivatives as Newton's me ...

(an iterative numerical method) are named after him. He was an Invited Speaker at the 1912

International Congress of Mathematicians The International Congress of Mathematicians (ICM) is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union (IMU). The Fields Medals, the Nevanlinna Prize (to be rename ...

(ICM) in Cambridge, England and at the 1924 ICM in Toronto.

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Johan Frederik Steffensen papirer
(Danish) 1873 births 1961 deaths Danish mathematicians Danish statisticians Danish actuaries {{Europe-mathematician-stub