Questions tagged [radicals]

For questions involving radical of numbers or radical of expressions (i.e. numbers/expressions raised to the power of a fraction).

A radical expression is any mathematical expression containing a radical symbol $~(√~)~$.

Many people mistakenly call this a 'square root' symbol, and many times it is used to determine the square root of a number. However, it can also be used to describe a cube root, a fourth root, or higher.

When the radical symbol is used to denote any root other than a square root, there will be a superscript number in the $'V'$-shaped part of the symbol. For example, $~3\sqrt{8}~$ means to find the cube root of $~8~$. If there is no superscript number, the radical expression is calling for the square root.

The term underneath the radical symbol is called the radicand.

Steps required for Simplifying Radicals:

Step $~1~$: Find the prime factorization of the number inside the radical. Start by dividing the number by the first prime number $~2~$ and continue dividing by $~2~$ until you get a decimal or remainder. Then divide by $~3,~ 5,~ 7,~$ etc. until the only numbers left are prime numbers. Click on the link to see some examples of Prime Factorization. Also factor any variables inside the radical.

Step $~2~$: Determine the index of the radical. The index tells you how many of a kind you need to put together to be able to move that number or variable from inside the radical to outside the radical. For example, if the index is $~2~$ (a square root), then you need two of a kind to move from inside the radical to outside the radical. If the index is $~3~$ (a cube root), then you need three of a kind to move from inside the radical to outside the radical.

Step $~3~$: Move each group of numbers or variables from inside the radical to outside the radical. If there are nor enough numbers or variables to make a group of two, three, or whatever is needed, then leave those numbers or variables inside the radical. Notice that each group of numbers or variables gets written once when they move outside the radical because they are now one group.

Step $~4~$: Simplify the expressions both inside and outside the radical by multiplying. Multiply all numbers and variables inside the radical together. Multiply all numbers and variables outside the radical together.

A closely related tag is the tag.

3729 questions
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Multiplying radicals by variables

Let's say I am to multiply $3x^2$ by ${\sqrt 8}$. Which answer is true and why? $3 {\sqrt 8x^2}$ or $3x^2 {\sqrt 8}$
Steve
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How to find the % Contribution of a Change of Terms within a Cube Root?

How do you find the contribution of an increase of each term within a cube root? Given that: $$result = \sqrt[3]{a*b*c}$$ Looking at how the result changes from say t0 to t1: $$result_0 = \sqrt[3]{a_0*b_0*c_0}$$ $$result_1 =…
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How to compute $\sqrt{1+2015\sqrt{1 + 2018 \cdot 2016}}$

I recently found a new math riddle that I couldn't solve, it ask you compute the following without a calculator: $$\sqrt{1+2015\sqrt{1 + 2018 \cdot 2016}}$$ I tried to rewrite both of 2016 as powers of two but I couldn't get anywhere close . How…
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Multiple radicals: $(\sqrt{10}+\sqrt{11}+\sqrt{12})(\sqrt{10}+\sqrt{11}-\sqrt{12})(\sqrt{10}-\sqrt{11}+\sqrt{12})(-\sqrt{10}+\sqrt{11}+\sqrt{12})$

$(\sqrt{10}+\sqrt{11}+\sqrt{12})(\sqrt{10}+\sqrt{11}-\sqrt{12})(\sqrt{10}-\sqrt{11}+\sqrt{12})(-\sqrt{10}+\sqrt{11}+\sqrt{12})$ I don't think multiplying these out will work, and I am stuck in the beginning, without a basic concept to get started.…
suomynonA
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radical expression

How would one approach the following problems : $\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-6\sqrt{20}}}}$ $(\frac12\sqrt{8}-3\sqrt{2}-\sqrt{10})*(\sqrt{2}+2\sqrt{1.6}-3\sqrt{0.4})$ I am not looking for actual solutions but for tips on how these type of…
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How to answer this kind of questions

How can I answer this kind of questions? I should prove the following $$\frac{1}{\sqrt{a_1} + \sqrt{a_2}} + \frac{1}{\sqrt{a_2} + \sqrt{a_3}} + \frac{1}{\sqrt{a_3} + \sqrt{a_4}} + ... + \frac{1}{\sqrt{a_{n-1}} + \sqrt{a_n}} = \frac{n-1}{\sqrt{a_1} +…
user274822
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How to multiply radicals?

The problem is $$0 = -(\sqrt{7 -2 b} - 2) * -\sqrt{7-2 b} - 2) $$ the original question was this $$-2 = \sqrt{7 -2 b} - \sqrt{2 b + 3}$$ and than i found out the you had to isolate one radical version so i substracted $$-(\sqrt{7 -2 b} - 2)$$ and…
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Value of an expression with cube root radical

What is the value of the following expression? $$\sqrt[3]{\ 17\sqrt{5}+38} - \sqrt[3]{17\sqrt{5}-38}$$
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Find the speed S by using radical equations

There are two word problems that I cannot write as radical equations. 1.A formula that is used for finding the speed s, in mph, that a car was going from the length L, in feet, of its skid marks can be written as s=2 square root of 5L. In 1964, a…
john
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What are these types of problems called?

I usually like watching "How-To" or a live video on how to do a math process. So what is the following problem type called? I know it includes radicals, but it's not just radicals, since you get things way simpler when just Google-ing "radicals."…
Mike Wentworth
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How does dividing radicals work?

Here I have the problem $\dfrac{5\sqrt{24}\cdot 3\sqrt{45}}{\sqrt{6}}$. Not sure how to actually type it out here. How do I actually solve it? The answer says $90\sqrt{5}$ but how?
Mike
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Any one help me solve Algebraically equation $\sqrt{x^2+x+1}+ x^{3}= \sqrt{2x+2}+x^{2}+x$

I can't solve this. Can any one show me detail solution $$ \sqrt{x^2+x+1}+x^3=\sqrt{2x+2}+x^2+x $$
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Infinite root out of x

I and my friend were sitting in the maths lesson and we suddenly came up with what infinite root out of x is equal to. And we came up with this this equation: $$ \sqrt[\infty]{x} = 1+ (x-1)×10^{-\infty} $$ I wonder if this makes any sense. (Im…
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How to simplify a fraction in a radical

how would you simplify a radical that has the fraction 8 divided by 27 aka 8/27. Step by step.
Sandy
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Simplifying this radical expression.

As homework I was asked to simply the following radical expression. $\sqrt{3ax^2+18ax+27a}$ Is following the farthest I can simplify the above expression ? $\sqrt{3a(x^2+6x+9)}$
user126456