Simply put, it is the result of the inverse operation of square = the original number with root sign.
For example: √4=2. Because 2 squared =4, √4=2.
Now, we are used to using radical symbols (such as, etc. ), and I think it is simple and convenient to use. Then, how did the radical sign come into being and evolve into what it is now?
In ancient times, Egyptians used the symbol ┌ to represent the square root. Indians wrote ka in front of the square root. Arabs use it to represent. 1840 years ago, the Germans used the dot "."to represent the square root, two dots "..." to represent the cube root, and three dots "..." maybe because they were written quickly and the endings were slender, they became ".1525. Rudolph used the radical sign for the first time in his algebra works. For example, he wrote that 4 is 2, 9 is 3, and it is represented by 8, 8. However, this writing method has not been generally recognized and adopted.
At the same time, some people use the capital r of the first letter in the Latin root of the word "root" to indicate the square operation, followed by the first letter q of Latin "square" or the first letter c of "cube" to indicate how many times the square has been opened. For example, at present, it is written as R.q.4352. Now, it is written by mathematician Bombelli. ╜ "is equivalent to the brackets used today, and p is equivalent to the plus sign used today (at that time, even the addition and subtraction signs"+"and"-"were not universal).
It was not until17th century that Descartes (1596-1650), a French mathematician, first used the radical sign used today. In a book, Descartes wrote: "If you want to find the square root of, write it;" If you want to find a cube root, write it. "
What is the consideration? Sometimes, many terms have been squared. In order to avoid confusion, Descartes connected these terms with a horizontal line, and put the root sign √ in front of them (but there is a small hook more than Rudolph's root sign), which is the current form of root sign.
The current cube root symbol appeared very late. It was not until18th century that we saw the use of symbols in a book, such as the cube root of 25. After that, the root symbols such as and so on gradually began to be used.
This shows how difficult it is to adopt a symbol universally. It is the result of long-term continuous improvement, selection and elimination. It is the crystallization of the collective wisdom of several scholars, not invented by one person out of thin air, nor did it fall from the sky.
The root sign is in the form of √ in the computer.