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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How can you take a square root of a negative number?

How can you take a square root of a negative number? Specifically, I have this problem where I need to select a positive integer $q$ s.t. for $b \in ]2,5[$, $$q > \sqrt{\frac{1}{b-5}}$$ and I want to be able to conclude that $$b <…
mavavilj
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How can I solve the following question?

How can I solve the following problem? $4\cdot 2\sqrt{x}=x^2$
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Rationalising a denominator

I have the question "Rationalise the denominator, simplifying where possible. $$\frac {\sqrt{3} }{ \sqrt{2} \left(\sqrt{6} - \sqrt{3} \right)}$$ I am not sure whether I should multiply the top and bottom as it is but reversing the sign so…
Dan
  • 1,649
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What does a comma mean in a square root?

We have this problem in my Discrete Math class: "Give the set to which each of the following numbers belong" and one of the numbers is "sqrt 93," what does the comma mean? I guess it could be a typo, but I don't want to just assume that. I can't…
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Which property of radicals is applied here?

A really quick and simple question. why is = which radical properties have been applied?
Daniele
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Prove that $\sqrt[n]{x} \cdot \sqrt[n]{y} = \sqrt[n]{x \cdot y}$

I am currently learning about properties of radicals in a high school math class, and I am curious as to why this property holds true? $\sqrt[n]{x} \cdot \sqrt[n]{y} = \sqrt[n]{x \cdot y}$ Could anyone intuitively explain this to me?
Nick
  • 315
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A coefficient that multiplies a radical expression

By what rules or axioms can you get this following answer? $k \sqrt[3]{k^2 + 1}$ Equal to $\sqrt[3]{k^5+k^3}$ ?
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If $a\sqrt{a} - 7\sqrt{a} = 2\sqrt{5}$ what is the value of $a-\sqrt{5a}$?

Actually this is a little urgent. While I was studying for the exam I encountered with this question. Neither my friends nor I could find the solution. It really seems easy though. Is there a short way or formula that I don't know?
ece
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Using quotient Rule with a problem that has radicals in it(having major issues simplifying...)

So i'm trying to remind myself of how to use the quotient rule, and when i try to differentiate the following problem i get major issues: (2x + x^3) / x^(1/2) I get to the following point... ((2 + 3x^3)(x^1/2) - 1/2(x^1/2)(2x+x^3)) / x How in gods…
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High school level radical expression

I am trying to simplify this expression $$\frac{\sqrt{x}+\sqrt{x+1}}{\sqrt{x}-\sqrt{x+1}}= $$ However, I am not certain if I am doing it right or if I am simplifying it far enough. The end doesn't really seem right to me. If someone can confirm or…
Mehdi
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Calculate the radicals (order 3)

Calculate: $ \sqrt[3]{5+2 \sqrt{13}} + \sqrt[3]{5-2 \sqrt{13}} $ I tried to note that expression with x and then cube it but then it becomes a complicated calculation
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Simplify the expresion

I want to simplify this expression $ a^{\frac{1}{6}} \sqrt[3]{a} - \frac{a^{\frac{2}{7}}}{\sqrt{a}} $ This has to give me $ \sqrt{a} - \sqrt[21]{a^5} $ , but I don't know how to get to that result
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Calculate the radicals

I want to calculate this expresion $ \sqrt {1-2 \sqrt[3]{6} + \sqrt[3]{36}} $ And this expresion I want to simplify it $ \frac {3 \sqrt{a}}{a} + a^{\frac{1}{6}} \sqrt[3]{a} - \frac{a^{\frac{2}{7}}}{\sqrt{a}} - \frac{3a^0}{\sqrt{a}} $ with a>0
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Solving radical Equation?

The question goes on about like this. $$-2 = \sqrt{7 -2 b} - \sqrt{2 b + 3}$$ I tried squaring both sides but than that does not make sense as one side has 2 square roots. Then do I double it, like $(-2)^4$ 'cause there are two of them?
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Square roots calculation without the use of a calculator

How do you find a square root of a number when the square root isn't a whole number, without a calculator Example: 35
Klayton
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