Columbia Encyclopedia

Search results

500 results found

secant

(Encyclopedia)secant, in mathematics. 1 In geometry, a secant is a straight line cutting a curve or surface. If it intersects the curve in two different points, as in the secant of a circle, the segment of the seca...

Fibonacci, Leonardo

(Encyclopedia)Fibonacci, Leonardo lāōnärˈdō fēbōnätˈchē [key], b. c.1170, d. after 1240, Italian mathematician, known also as Leonardo da Pisa. In Liber abaci (1202, 2d ed. 1228), for centuries a standard...

Freundlich, Erwin Finlay

(Encyclopedia)Freundlich, Erwin Finlay froindˈlĭkh [key], 1885–1964, German astronomer. Freundlich obtained a doctorate in mathematics at Göttingen, then joined the Royal Observatory at Berlin, where he worked...

plane

(Encyclopedia)plane, in mathematics, flat surface of infinite extent but no thickness. An example of a plane, or more exactly of a bounded portion of a plane, is the surface forming one face, or side, of a cube. A ...

National Defense Education Act

(Encyclopedia)National Defense Education Act (NDEA), federal legislation passed in 1958 providing aid to education in the United States at all levels, public and private. NDEA was instituted primarily to stimulate ...

Parisi, Giorgio

(Encyclopedia)Parisi, Giorgio, 1948–, Italian physicist, Ph.D. Sapienza University of Rome, 1970. Parisi is Professor of Theoretical Physics at Sapienza University....

Cauchy, Augustin Louis, Baron

(Encyclopedia)Cauchy, Augustin Louis, Baron ōgüstăNˈ lwē bärôNˈ kōshēˈ [key], 1789–1857, French mathematician. He was professor simultaneously (1816–30) at the École polytechnique, the Sorbonne, and...

Perry, William James

(Encyclopedia)Perry, William James, 1927–, U.S. government official, b. Vandergrift, Pa. A Ph.D. in mathematics, former Stanford engineering professor, and founder of a military electronics firm, he served (1977�...

Bedford, John of Lancaster, duke of

(Encyclopedia)Bedford, John of Lancaster, duke of, 1389–1435, English nobleman; third son of Henry IV of England and brother of Henry V. At the death (1422) of his brother and succession of his 9-month-old nephew...

York, Edmund of Langley, duke of

(Encyclopedia)York, Edmund of Langley, duke of, 1341–1402, fifth son of Edward III of England. He was made (1362) earl of Cambridge, served on expeditions to Spain and France, and married (1372) Isabel, daughter ...