Radical

What does the term Radical in mathematics denote?


The term ‘Radical’ is derived from a Latin word “latex” meaning a root as in the root of a plant. 


Radical in math denotes ROOTS, typically square roots.


Let’s take an example to understand this better.

 \[\sqrt{5}\] is read as the square root of 5.


or also "radical 5."


If we have the "cube (3) root" or the "fourth(4th) root" etc., the word radical is rarely used.


What is a Radical Symbol?

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The radical symbol √ in the subject of mathematics denotes the “root” of that digit. 


Radical symbol is employed to signify one of the two inverse operations for exponentiation. Explicitly, it takes the end result of the exponentiation and the exponent used to get it and yields back the base used to get that result with that exponent. In layman's terms, it finds the number that, if multiplied by itself the number of times indicated by the little number by the radical (index), the result will be the number underneath the radical (radicand). If no index is displayed, then the index is 2.


Radicals are generally indicated as fractional (non-integer) powers. You would see \[x^{(\frac{1}{2})}\], \[x^{(\frac{2}{3})}\], \[x^{(\frac{12}{5})}\] as samples. They operate under the simple multiplicative law for exponents, \[(x^{m})\] *\[(x^{n})\] = \[x^{(m+n)}\]. In real numbers, you usually want the Principal Value, so sqrt (4) =2 not -2. You can nest them as well, \[\sqrt{(3 - 2\times \sqrt{(2)}})\] = \[\sqrt{(\sqrt{(2)-1})^{2}})\] = \[\sqrt{(2)}\] - 1


What is a compound radical expression?

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In the above-mentioned radical expression, 


“n” is called the index, 


“x” is said to be the radicand, and 


The math symbol representing the taking of roots is the sign of radical as we already know. 


Degree of Radical

The index signifies what root is being taken. If there is no index written, it is understood to be 2, a square root. 


When it comes to math, a radical symbol √ is used to represent a radical expression but many people misguidedly read this as a 'square root' symbol, and multiple times it is employed to conclude the square root of a number. However, apart from square roots, it can also be used to denote a cube root, a fourth root, or higher with numbers written in its place accordingly. But it is just in the case of square root that no number is written over the radical symbol.


Now there are a few restrictions on the above-mentioned radical expression that should be kept in mind: 

  • The first factor to keep in mind is that the index, also denoted as “n“ must be a positive integer which is greater than or equal to 2. 

  • The second factor states that the radicand also denoted as “x” must be a real number only. 

  • The third factor being that if the index or “n” is an even integer then the radicand or “x” must be either greater than or equal to the value of zero in order to represent a real number. On the other hand, if the radicand or “x” is an odd number and a negative radicand it will always represent a real number value. 


How do we Find the Simplest Radical Form of a Square Root? 

In order to find the simplest radical form of a square root, you need to perform prime factorization of the number. To do this, we need to take a number first and start dividing it by various prime numbers till the time all its factors are now prime. 


Let us try and find the simplest radical form of number 24. 


24, when divided by the smallest divisible prime number 2, gives 12. 12 divided by 2, is 6. 6 divided by 2 is 3. 


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Therefore, the prime factorization of 24 is \[2^{3}\] * 3, which in the simplified form means 8 * 3. In the next step, the pair of the same numbers are taken out and kept out of the root symbol. Your placement of the number outside the root symbol should be kept in mind which will otherwise signify that the number placed outside is multiplying the square root of number 24. In this case, there is only one pair in this prime factorization i.e. 2 which will be taken out which leaves us with square root six - time 2 which is the actual answer. 


Also know that while we are taking out these pairs, only one digit out of the pair is taken which in this case is number 2 which is kept on the outside of the square root symbol. 


Multiplication of Radicals 

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Radicals show an easy method of multiplication. For this, all you need to do is multiply the required radical outside the radical sign by the ones inside the symbols. 


A radical equation is the one that has minimum one variable expression within a radical, most often the square root.


Solved Examples:

Simplify 2\[\sqrt{4}\]+2\[\sqrt{824}\] + 28.

Simplifying:

Just like with any other expression, when we have a radical expression, we look to form like terms. In this case, like terms are ones that have the same number under the radical signs.


Answer and Explanation:

We can simplify the expression as follows.


\[2\sqrt{4} + 2\sqrt{8}\] = \[2\sqrt{4} + 2\sqrt{2} *4\] = 2 ∗ 2 + 2 ∗ \[2\sqrt{2}\] = \[4 + 4\sqrt{2}\]

∴\[2\sqrt{4} +2\sqrt{8}\] = \[4(1+ \sqrt{2})24 + 28\] = 24 + 22 = 2 ∗ 2 + 2 ∗ 22 = 4 + 42 

∴ \[2\sqrt{4} + 2\sqrt{8}\] = 4(1+2).

FAQ (Frequently Asked Questions)

1. What is the Root of a Number?

The root of a number is when, this number is multiplied by itself and gives a result, the multiplication of the same will be depending on the value of the root, if it is a square root it is multiplied twice and if it is cubic it will be three times, the roots are of the following form √a where n is the index of the root and aa is the amount sub radical or rooting the symbol √ is called radical. It should be noted that even index roots do not accept negative numbers, only odd index roots have results for this type of number.

2. What are the Properties of a Number Root?

The roots have properties just like most of the mathematical operations, some of the properties it has are; multiplication of roots with the same index, having two roots which are multiplied and are of the same index, the same root will be placed and the sub radical quantities will be multiplied, in the division of roots with equal indexes they are also placed in the same root and the sub radical quantities are divided, for the addition and subtraction of roots it is only applied to the equal roots adding or subtracting the coefficients of each one of them.