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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Prove that condition is rational

I tried to solve this about hour, but I can't... $$\begin{align} \sqrt{7+4\sqrt{3}} - \sqrt{3} \end{align}$$ Answer should be 2. I don't need to solve this for me, I just need explanation how to solve this condition. Thanks.
gintko
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An Introduction to Simplifying Radicals

How would I simplify 30 radical 45? Neither number is perfect square, I don't think. So I'm confused as to how to do it.
Mike Wentworth
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square root of 2 to decimal

I need to know what calculation needs to be done to get "1.4142135623730950488016887242097" from √2 (square root 2) I've seen wiki (below link), but didn't yet understand how it's get done. http://en.wikipedia.org/wiki/Square_root_of_2 anyone who…
kamal pal
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simplifying the quotient of two radical expressions

How do we find $p$ and $q$ so that $$\frac{\sqrt{2}+2}{\sqrt{2}-1}=p+q\sqrt{2}\,?$$
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How to solve $y = \sqrt{k\sqrt{k\sqrt{k \sqrt{k\sqrt{\dots}}}}}$?

$\text{Given}\quad y = \sqrt{k\sqrt{k\sqrt{k \sqrt{k\sqrt{\dots}}}}}\quad \text{ where }\,k\geq 0,\;\;\text{find the value of }\,y.$ I have no idea on how to solve problems like this.
Vansh
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I don't understand one of the steps in solving this equation.

I'm very rusty... it's been a few years since I've touched radicals and algebra. I had to solve for $k$ in the course of a Physics problem, and I realized I didn't remember how to do this. $$10=\sqrt{\frac k {0.05}}$$ So I went to Wolfram Alpha and…
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How do you simplify radicals with numerator

Square root of 18/3 I don't understand how you simplify this. No clue, I only understand to simplify the denominator. Thank You
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Compute the smallest possible integer $x$ such that $\lfloor \sqrt[8]{x}\rfloor < \lfloor \sqrt[7]{x}\rfloor < ... \lfloor \sqrt{x}\rfloor < x$

Compute the smallest positive integer $x$ such that $\lfloor \sqrt[8]{x}\rfloor <\lfloor \sqrt[7]{x}\rfloor <\lfloor \sqrt[6]{x}\rfloor <\lfloor \sqrt[5]{x}\rfloor <\lfloor \sqrt[4]{x}\rfloor <\lfloor \sqrt[3]{x}\rfloor <\lfloor \sqrt{x}\rfloor <…
dexgyd
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Real-base powers and fractional exponent

We suppose that $a\in\Bbb R^{+}_0$ we know that $$a^{\frac{m}{n}}=\sqrt[n]{a^m} \tag 1$$ Is $(1)$ provable or is it a given definition. Many years ago I remember that perhaps there was a proof of such an equality. Does anyone remember it? Thank you…
Sebastiano
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simplify radicals and fractional exponents?

This is the equation, please help me. I don't have any idea what to do with this. Thank you. √((32)^((4)/(5))(2^(n+1))^(4))/8^3 (16)^(n-1) That is a whole fraction within a radical sign all over…
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Confusion about the conjugate (square roots)

In this Wikipedia article it says: "In mathematics, the conjugate of an expression of the form $a+b\sqrt{d}$ is $a-b\sqrt{d}$, provided that $\sqrt{d}$ does not appear in $a$ and $b$." Why can't $\sqrt{d}$ appear in $a$ and $b$? In my textbook it is…
Hilbert
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Square root from double radical

I'm learning math, and found some interesting example. $$ \sqrt {2-\sqrt 3} = \frac{1}{\sqrt {2+\sqrt 3}} $$ Can you please explain me, why this happend. I guess that it depend on limits, but I still don't understand
mxxnseat
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How to simplify this expression with a cube root?

Here is a task from my son's math paper: The problem is besides not knowing how to simplify this expression (my math was terribly bad at school and it's already been a long time since that time) I can't quite get it whether it is 125 raised to the…
brilliant
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Is an even root of a negative number to the mth power undefined?

We know by definition that: $$\sqrt[n]{a^m}=(\sqrt[n]{a})^m$$ Having said that, I can't help but wonder if this is always the case. Specifically, if $a$ is a negative number and $n$ is even. Take for instance the 6th root of $-2$ to the power of…
Zikta
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Square Root Subtraction Question

Is there any way I can simplify the equation $ \sqrt{a-b}-\sqrt{a}$ ? I understand that there is no way to simplify $ \sqrt{a} - \sqrt{b} $