Q.E.D.

Q.E.D. is an acronym or initialism of the Latin phrase quod erat demonstrandum, which means "what was to be demonstrated". In other words, Q.E.D. means "something was to be proven, and now it has been done".^[1]^[2]

History

In the European Renaissance, scholars often wrote in Latin. The phrases Q.E.D. was often used at the end of mathematical or philosophical proofs.^[3]

Equivalents in other languages

Q.E.D. is used in many languages, including:

Language	Abbreviations	Stands for...
Arabic	و.هـ.م	وهو المطلوب إثباته
Bengali	অ. সি.	অতঃ সিদ্ধ
Chinese	证毕。	证明完毕
Croatian	Š.T.D.	što je trebalo dokazati
Czech	C.B.D.	což bylo dokázati
Esperanto	K.E.P	kio estis pruvenda
Estonian	M.O.T.T.	mida oligi tarvis tõestada
Finnish	M.O.T.	mikä on todistettu
French	C.Q.F.D.	ce qu'il fallait démontrer
German	w.z.b.w.	was zu beweisen war
Greek	Ο.Ε.Δ.	όπερ έδει δείξαι
Italian	C.V.D.	come volevasi dimostrare
Hebrew	.מ.ש.ל	מה שצריך להוכיח
Hindi	इ.सि.	इति सिद्धम्
Polish	c.b.d.u.	co było do udowodnienia
Portuguese	C.Q.D.	como queríamos demonstrar
Russian	ч.т.д.	что и требовалось доказать
Serbian	ш.т.д.	што је и требало доказати
Slovenian	q.e.d	(quonc)/konc enga dokaza
Tamil	நி.வே.	நிரூபிக்கப்படவேண்டியது
Thai	ซ.ต.พ.	ซึ่งต้องพิสูจน์
Hungarian	E.K.B.	Ezt kellett bizonyítani
Spanish	Q.E.D.	queda entonces demostrado queda esto demostrado
Swedish	V.S.B. V.S.V	vilket skulle bevisas vilket skulle visas
Vietnamese	đpcm.	Điều phải chứng minh

Q.E.D. Media

A 1604 use of "quod erat demonstrandum". Latin text:8.
Spinoza's original text of Ethics, Part 1, Q.E.D. is used at the end of Demonstratio of Propositio III on the right hand page

Related pages

Mathematical proof

References

↑ "The Definitive Glossary of Higher Mathematical Jargon: Q.E.D." Math Vault. 2019-08-01. Retrieved 2020-09-06.
↑ Ben-Menahem, Ari. (2009). Historical Encyclopedia of Natural and Mathematical Sciences, Vol. 1, p. 5603; Fergusson, Rosalind. (2009). Shorter Dictionary of Catch Phrases, p. 109.
↑ Weisstein, Eric W. "Q.E.D." mathworld.wolfram.com. Retrieved 2020-09-06.

Other websites

Earliest Known Uses of Some of the Words of Mathematics (Q)

[1] "The Definitive Glossary of Higher Mathematical Jargon: Q.E.D." Math Vault. 2019-08-01. Retrieved 2020-09-06.

[2] Ben-Menahem, Ari. (2009). Historical Encyclopedia of Natural and Mathematical Sciences, Vol. 1, p. 5603; Fergusson, Rosalind. (2009). Shorter Dictionary of Catch Phrases, p. 109.

[3] Weisstein, Eric W. "Q.E.D." mathworld.wolfram.com. Retrieved 2020-09-06.

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