Why Do We Use X for the Unknown?

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Why Do We Use X for the Unknown? · 1:30 · Intellect Plus

In short: This short history follows how algebra learned to name the unknown, from the Egyptian 'aha' to the z, y and x of Descartes, and explains why the choice of x itself is still uncertain.

A 1:30 short film in the series “From Fingers to Qubits”, narrated by intellect_voice_01.

Sources used in this film: SciHi blog (PDF hosted on the MacTutor History of Mathematics archive, University of St Andrews), “sci_hi”; MacTutor History of Mathematics, School of Mathematics and Statistics, University of St Andrews, “Arabic mathematics”; British Museum, “papyrus | British Museum”; Internet Archive (digitised book from the collections of the National Central Library of Rome, via European Libraries), “Francisci Vietae In artem analyticem isagoge seorsim excussa ab Opere restitutae mathematicae analyseos, seu Algebra noua : François Viète : Free Download, Borrow, and Streaming : Internet Archive”; SciHi Blog (PDF hosted by the MacTutor History of Mathematics archive, University of St Andrews), “sci_hi”; Internet Archive (digitised text of Florian Cajori, "A History of Mathematical Notations", Vol. I, Open Court Publishing Company, 1928), “Full text of "A history of mathematical notations"”; Internet Archive (digitised text of Florian Cajori, A History of Mathematical Notations, Vol. I, Open Court Publishing Company, 1928), “Full text of "A History Of Mathematical Notations Vol I"”; Scientific American (reprinted from The Conversation; author Peter Schumer, Middlebury College), “The Mysterious Origins of 'X' in Algebra”; Smithsonian Magazine (republished from The Conversation; author Peter Schumer, Middlebury College), “A Brief History of the Letter 'X,' From Algebra to X-Mas to Elon Musk”; MacTutor History of Mathematics, University of St Andrews (Jeff Miller's 'Earliest Uses of Symbols' pages), “Earliest Uses of Symbols for Variables - MacTutor History of Mathematics”; Springer (Mathematics Education Research Journal), article by Robert Ely & Anne E. Adams, “Unknown, placeholder, or variable: what is x?”; Encyclopaedia Britannica, “Mathematics | Definition, History, & Importance”; Stanford Encyclopedia of Philosophy, “Descartes’ Mathematics”.

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