Matematikteki bilinmeyen "x" nedir?

[akahya]

Matematiğinde bir bilim olduğunu düşünerek konuyu buraya açtım. Bilgi uzaklardan geliyor. Japonya'dan İsmail Tirtom hocamdan. Kendisi bir mühendis olmasına rağmen dikkatini çekmiş benimle paylaştı bende size aktarıyorum.

"Matematikteki x'in kaynağı Arapça cebir kitapları çevrilirken, bizimde kullanığımız 'şey' kelimesinin, İspanyolca yada Latince tercümesinin zaman içindeki dönüşümü imiş."

History
The symbol x commonly denotes an unknown variable. Even though any letter can be used, x is the most common choice. This usage can be traced back to the Arabic word šay' شيء = “thing,” which in translated algebra texts and similar was taken into Old Spanish with the pronunciation “šei,” which was written xei, which was soon habitually abbreviated to x. (The Spanish pronunciation of “x” has changed since). Some sources say that this x is an abbreviation of Latin causa, which was a translation of Arabic شيء. That started the habit of using letters to represent quantities in algebra. In mathematics, an “italicized x” () is often used to avoid potential confusion with the multiplication symbol. By extension beyond mathematics, “X” has come to represent a generic placeholder variable whose value is unknown or secret, as in project X or mister X.

kaynak; wikipedia