Why Is “X” The Unknown ? By Terry Moore [TED Summary]

In mathematics, the letter "x" represents an unknown variable. It's also arguably one of the most popular in its packaging. We can see everywhere: Generation X, X-Files, and TEDx.

So why does "x" represent the unknown?

Terry says that, A few years ago, he decided to start learning Arabic. He considered it a very precise language and full of information. Learning a language, and even speaking, is similar to composing a mathematical equation. Perhaps this is why everything we know as science, engineering, and mathematics has derivation in the Arabic system, especially algebra.

When Arabic texts entered Spain in the 11th century, Europe wanted to translate this mathematical wisdom from the East into a written Western language. Attempts to do so, however, proved problematic. As it turns out, the Arabic voice does not translate well into European speech patterns, nor is there sufficient character to represent these voices.

The Arabic word meaning "the unknown," a word used along the earliest mathematical proof, contains the Arabic letter "sheen." . The problem is, Moore explains, there is no "sh" sound in Spanish. Thus, the language craftmen borrow the "ka" sound from the Greek letter χ or "chi." Then, chi is replaced with the Latin letter X. And once the material is translated into Latin, this book forms the material for the mathematical textbook we continue to use and read today.

So why is the letter "x" unknown ?

Because you can not say "sh" in Spanish!