From Wikipedia, the free encyclopedia Caspar Wessel
Caspar Wessel
Caspar Wessel lines. This line is the sum of the united lines". This is the
same idea as used today when summing vectors.
Born June 8, 1745(1745-06-08) Wessel’s priority to the idea of a complex number as
Vestby
a point in the complex plane is today universally recog-
Died March 25, 1818(1818-03-25) (aged 72) nised. His paper was re-issued in French translation in
Copenhagen 1899, and in English in 1999 as On the analytic representa-
Nationality tion of direction (ed. J. Lützen et al.).
Danish
Wessel’s elder brother Johan Herman Wessel was a
Norwegian major name in Danish-Norwegian literature.
Fields Mathematics
Alma mater University of Copenhagen External links
Known for Complex numbers • O’Connor, John J.; Robertson, Edmund F., "Caspar
Complex plane Wessel", MacTutor History of Mathematics archive,
Vectors University of St Andrews, http://www-
history.mcs.st-andrews.ac.uk/Biographies/
Caspar Wessel (June 8, 1745, Vestby – March 25, 1818, Wessel.html .
Copenhagen) was a Norwegian-Danish mathematician
Persondata
and cartographer. In 1799, Wessel was the first person to
describe the geometrical interpretation of complex num- Name Wessel, Caspar
bers as points in the complex plane. He was the younger Alternative names
brother of poet and playwright Johan Herman Wessel. Short description
Date of birth June 8, 1745
Biography Place of birth
Wessel was born in Jonsrud, Vestby, Akershus, Norway. Date of death March 25, 1818
In 1763, having completed secondary school, he went to
Place of death
Denmark for further studies. He attended the University
of Copenhagen and acquired the degree of candidatus juris
in 1778. From 1794, however, he was employed as a sur-
veyor (from 1798 as Royal inspector of Surveying).
It was the mathematical aspect of surveying that led
him to exploring the geometrical significance of complex
numbers. His fundamental paper, Om directionens ana-
lytiske betegning, was published in 1799 by the Royal Dan-
ish Academy of Sciences and Letters. Since it was in Dan-
ish, it passed almost unnoticed, and the same results
were later independently rediscovered by Argand in 1806
and Gauss in 1831.
One of the more prominent ideas presented in "On
the Analytical Representation of Direction" was that of
vectors. Even though this was not Wessel’s main inten-
tion with the publication, he felt that a geometrical con-
cept of numbers, with length and direction, was needed.
Wessel’s approach on addition was: "Two straight lines
are added if we unite them in such a way that the second
line begins where the first one ends and then pass a
straight line from the first to the last point of the united
Retrieved from "http://en.wikipedia.org/w/index.php?title=Caspar_Wessel&oldid=468947156"
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From Wikipedia, the free encyclopedia Caspar Wessel
Categories:
• Danish mathematicians
• Norwegian mathematicians
• 18th-century mathematicians
• 19th-century mathematicians
• University of Copenhagen alumni
• Complex numbers
• 1745 births
• 1818 deaths
• 18th-century Norwegian people
• Norwegian scientist stubs
• Danish scientist stubs
• European mathematician stubs
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