Anders Lindstedt [SEP] occupation
Anders Lindstedt
Anders Lindstedt (27 June 1854 – 16 May 1939) was a Swedish mathematician, astronomer, and actuarial scientist, known for the Lindstedt-Poincaré method.
Life and work.
Lindstedt was born in a small village in the district of Sundborns, Dalecarlia a province in central Sweden. He obtained a PhD from the University of Lund aged 32 and was subsequently appointed as a lecturer in astronomy. He later went on to a position at the University of Dorpat (then belonging to Russia, now University
Poincaré–Lindstedt method
In perturbation theory, the Poincaré–Lindstedt method or Lindstedt–Poincaré method is a technique for uniformly approximating periodic solutions to ordinary differential equations, when regular perturbation approaches fail. The method removes secular terms—terms growing without bound—arising in the straightforward application of perturbation theory to weakly nonlinear problems with finite oscillatory solutions.
The method is named after Henri Poincaré, and Anders Lindstedt.
Example: the Duffing equation.
The undamped, unforced Duffing equation is given by
for "t