The symbol “=” was invented in 1557 by Robert Recorde, who was tired of writing “is equal to” repeatedly.

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The symbol “=” was invented in 1557 by Robert Recorde, who was tired of writing “is equal to” repeatedly.
Revolutionary events were changing Europe in the early 1500’s: the printing press; Asian trade; American exploration; the Reformation. The Italian peninsula was not one country but a collection of city-states with many wealthy and cosmopolitan traders. Modern algebraic notation did not exist at this time. Designating variables by letters was invented by Viète in 1591. (He used consonants for constants and vowels for variables.) Writing superscript for repeated multiplication is due to James Hume—in 1636 he used Aⅱ, Aⅲ, Aⅳ, …. Even +, –, and √ were new, having been introduced in 1486 by Johannes Widman. × was introduced by William Oughtred in 1631 and ÷ by Johann Rann in 1659. Our «equals symbol» = was introduced by Robert Recorde in 1557, in his Whetstone of Witte: And to avoide the tediouse repetition of these woordes: is equal to: I will lette as I doe often in woorke use, a paire of paralleles, or gemowe lines of one lengthe, thus: ═, because noe 2 thynges, can be moare equalle. (gemowe is an obsolete word meaning twin or, in this case, parallel.)
Joseph J Rotman (1995)
citing Robert Recorde (1557), Johann Rann (1659), William Oughtred (1631), Johannes Widman (1486), James Hume (1636), and François Viète (1591)
Though many stones doe beare greate price, The whetstone is for exercise As neadfulle, and in woorke as straunge: Dulle things are harde it will so chaunge, And make them sharpe, to right good vse: All artesmen know, their can not chuse, But vse his helpe; yet as men see, Noe sharpnesse semeth in it to bee. The grounde of artes did brede this stone: His Vse is greate, and moare then one. Here if you list your wittes to whette, Moche sharpnesse therby shal you gette. Dull wittes hereby doe greately mende, Sharp wittes are fined to their full ende Now proue, and praise, as you doe find, And to yourself be not vnkinde.
The Whetstone of Witte by Robert Recorde
Robert Recorde zamanından önce bu dünyaya gelen ve trajik bir sonla aramızdan ayrılan bilim insanlarından biri idi. 16. yüzyılda ekonomi, tıp, matematik, teoloji üzerine birçok çalışma yaptı. Ama onu günümüzde unutulmaz kılan, matematikte olmazsa olmaz eşit işaretini bize kazandırması oldu. 1510 doğumlu Recorde başarılı bir öğrencilik hayatı geçirdi, 14 yaşındayken Oxford Üniversitesi’ne gitti, devamında Oxford …
Robert Recorde zamanından önce bu dünyaya gelen ve trajik bir sonla aramızdan ayrılan bilim insanlar
How the equals sign changed the world |
500 years ago, tragic Welsh genius Robert Recorde wanted to teach maths to normal people.
Robert Recorde was one of those people so extraordinarily ahead of his time that he seemed destined to come to a tragic end. In the 16th century, he made advances in economics, medicine, theology, and poetry. But his greatest contribution is taught to every elementary school child, and it arguably laid the groundwork for modern computer science. He invented the equals sign.
(via How the equals sign changed the world | Ars Technica UK)
The strange and righteous history of the equals sign
The strange and righteous history of the equals sign
Enlarge / This plaque honoring Robert Recorde is at the Tenby Museum in Wales. (credit: Tenby Museum) Robert Recorde was one of those people so extraordinarily ahead of his time that he seemed destined to come to a tragic end. In the 16th century, he made advances in economics, medicine, theology… Read entire story.
Source: Ars Technica
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Pythagoras Oktober 1997
Het =-teken is hier al eerder ter sprake geweest. Het stuk in Pythagoras gaat over de geschiedenis van dit teken en over `concurrerende' tekens. Dit is het eerste van vijf stukjes over wiskundige notaties.