Square Root Symbol
About Square Root Symbol
√ is the square root symbol, also known as the radical sign, representing the principal square root of a number in mathematics. The square root symbol √ is fundamental in algebra, geometry, and calculus, denoting the number that when multiplied by itself gives the original value.
The square root symbol √ consists of a check-mark-like radical with a horizontal bar (vinculum) extending over the expression. As a Unicode character, the square root symbol holds codepoint U+221A within the Mathematical Operators block. The square root symbol frequently appears alongside the plus minus symbol ± when expressing both positive and negative roots of squared equations.
【Historical Origin】 The square root symbol evolved from the Latin letter "r" for "radix" (root). First appearing in print in 1525 by German mathematician Christoff Rudolff, the square root symbol gradually acquired its current form with the vinculum extending over the radicand. The square root symbol became standard notation during the development of modern algebra.
【Modern Applications】 Today the square root symbol is essential in mathematics education, engineering calculations, and computer science algorithms. The square root symbol pairs with the plus minus symbol ± to express dual solutions, and appears in the quadratic formula, Pythagorean theorem, and standard deviation calculations involving the sigma symbol σ.
How to Type Square Root Symbol
Windows Input
Method 1: Hold Alt and type 8730 on the numeric keypad; Method 2: Type pingfanggen in Chinese input method; Method 3: Use Character Map to copy the square root symbol.
Mac Input
Method 1: Press Option + V to directly type the square root symbol √; Method 2: Press Control + Command + Space and search "square root"; Method 3: Use the Character Viewer for the radical sign.
HTML/CSS Input
HTML: √ or √ or √; CSS: content: "\221A";
LaTeX Input
Use \sqrt{} for the square root symbol √ in LaTeX. Place the radicand inside braces: \sqrt{x}. For nth roots, use \sqrt[n]{x} for proper rendering of the radical symbol.
Square Root Symbol FAQ
What does the square root symbol √ mean?
The square root symbol √ denotes the number that when multiplied by itself equals the given value. For example, √9 = 3 because 3×3 = 9. The square root symbol with a vinculum extending over the expression indicates the principal (non-negative) square root.
How is the square root symbol related to the plus minus sign?
When solving x²=4, the solution is x=±√4, using the plus minus symbol ± with the square root symbol to indicate both positive and negative roots. This pairing of the square root symbol and plus minus symbol is standard for expressing complete solution sets.
What is the difference between √ and the cubed root symbol?
The square root symbol √ indicates the second root (square root), while the cubed root adds a small 3 in the radical's hook position (∛) to indicate the third root. The square root symbol is the most common radical, but higher-order roots extend the same notation.
What is the Unicode for the square root symbol?
The Unicode codepoint for the square root symbol √ is U+221A. Its named HTML entity is √ and decimal reference is √. The square root symbol resides in the Mathematical Operators block with excellent cross-platform support.