John Landen facts for kids
John Landen (born January 23, 1719 – died January 15, 1790) was an English mathematician. He made important discoveries in mathematics during his lifetime.
Life of a Mathematician
John Landen was born in Peakirk, a village near Peterborough in Northamptonshire, England. This was on January 28, 1719. He first trained to be a surveyor. A surveyor measures and maps land. From 1762 to 1788, he worked as a land agent for Earl Fitzwilliam. This meant he managed the Earl's land.
Even with his job, John Landen loved mathematics. He studied it in his free time. In 1744, he started writing for a magazine called Ladies' Diary. He published his own book, Mathematical Lucubrations, in 1755. From 1754 onwards, he shared his important math ideas with the Royal Society. The Royal Society is a famous group that promotes science.
Landen worked on a type of math called "fluxionary calculus." He tried to create a new way to solve these problems using only algebra. He wrote about this in the first part of his book, Residual Analysis. Another famous mathematician, Lagrange, continued his work. Sadly, the second part of Landen's book was never published.
Key Discoveries
One of Landen's most famous discoveries is called Landen's transformation. This is a special math rule. It helps to describe a curved line (a hyperbolic arc) using two other curved lines (elliptic arcs). He shared this discovery in the Philosophical Transactions in 1775. He also showed how to use it in his book, Mathematical Memoirs, in 1780.
On March 17, 1785, Landen presented new ideas about how things spin (rotary motion) to the Royal Society. His findings were different from those of other famous mathematicians, Euler and D'Alembert. He defended his ideas in the second volume of his Mathematical Memoirs. He finished this book while he was very ill. He received the printed book just one day before he passed away.
In the same book, he solved the puzzle of a spinning top. He also explained a mistake Newton had made. This mistake was about how the Earth's tilt changes over time, known as precession.
John Landen became a fellow of the Royal Society on January 16, 1766. This was a great honor. He was also a member of the Spalding Society. Even though mathematicians from other countries thought highly of him, he didn't always fully develop or combine his discoveries. He lived a quiet life, mostly in Walton, Northamptonshire. He died on January 15, 1790, at Milton, near Peterborough.
Works and Publications
John Landen wrote many important mathematical papers and books. Here are some of his main works:
- The Ladies' Diary: He contributed many articles to this magazine from 1744 to 1760.
- Papers in the Phil. Trans.: He published several papers in the Philosophical Transactions of the Royal Society (1754, 1760, 1768, 1771, 1775, 1777, 1785).
- Mathematical Lucubrations (1755): This was his first published book.
- A Discourse concerning the Residual Analysis (1758): This book discussed his new algebraic method.
- The Residual Analysis, book i. (1764): The first part of his major work on residual analysis.
- Animadversions on Dr Stewarts Method of computing the Sun's Distance from the Earth (1771): A critical look at another mathematician's work.
- Mathematical Memoirs (1780, 1789): A two-volume collection of his mathematical studies and discoveries.
