Why is the 'x' unknown?

I have the answer to the question that we all ask. The question is "Why is the 'x' known?" We all know that we learned that in Mathematics class in our elementary school but this question is everywhere now; the 'x price', 'x files', 'x projects', 'x number things'. Where did that come from? Why is only 'x' unknown? Why not anything else?

It will surprise you if I say that it came from Arabic. Arabic is a supremely logical language, to write a phrase or word or sentence in Arabic is like crafting an equation because every part is very precise and carry a lot of information. This is one of the reason that so much of what we have come to think as Western Science and mathematics and engineering was really worked out in the first few centuries of the common era by the Persian and Arabic and Turkish. This includes the little system in Arabic called Al-Jebr and Al-Jebr which roughly translates to the system for reconciling disparate parts. (Al-Jebr finally gave inspiration to the English word "Algebra")

The Arabic text containing these Mathematical wisdom finally made way to Europe through Spain in the 11th and 12th century. And when they arrived, there were tremendous interest in translating this into the European language but there were problems. There are some sound in Arabic which do not make into European language without lots of practice. Those sound cannot be represented by any of the existing characters present in the European vocabulary. Here is one example: the letter sheen (as seen in the image below) makes a sound as 'sh'. It is also the first letter of the word Shayan(pronounced Shaa - yon as in Boron) which means 'something" just like in English meaning some undefined, some unknown thing.

letter sheen pronounced as 'sh' 

Now in Arabic we can make this definite by adding definite article 'Al' so it becomes 'Al-Shayan' which meant 'the unknown thing' and this word is used through the early Mathematics equations and problems such as in this 10th century derivation of roots.

word 'shayon' as seen in the derivation of the roots in in 10th century

The problem with the medieval Spanish scholars who were entrusted with translation of these materials is that the letter Sheen and the word Shayan cant be rendered in Spanish because Spanish doesn't have that 'sh' word or anything which sounded like 'sh'. So by convention they borrowed the 'ck' sound as the 'kkeh' sound from the classical Greek as in letter 'kai' later when this material was translated into the more common European language so as to say in Latin language they simply replaced the letter 'kai' with Latin letter 'x' and once that happened it formed the basis of mathematics text book for almost 600 years.

Greek letter 'Chai'

letter 'x' in English

Now we have the answer to our question "Why is the letter 'x' unknown?" And the answer is that it is unknown because you can't say 'sh' in Spanish.








src>>>> ted.com