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.

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If I assume that the variables are positive number, should I put absolute value when taking them of out of a square root?

If I assume that the variables are positive number, should I put absolute value when taking them of out of a square root? like if I assumed that u is a positive number and I have square root u to the power 2. Should it be |u| or u?
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Simplification of Addition of Radicals

I know this may be a basic question, but I cannot seem to get the right simplification process for the following equation: $\sqrt{36+64+5^2} + \sqrt{20}$ I do know that the correct answer is 7√5, but I cannot seem to arrive at this answer. This is…
Rook
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Simplify a radical and integer sums

I have recently encountered the problem of finding $\sqrt {3 + 2\sqrt 2}$. I have tried many things, such as squaring $3 + 2\sqrt 2$, which leads to $17 + 12\sqrt 2$, and multiplying it $\sqrt {3 - 2\sqrt 2}$, but none of these seem to get me close…
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Why does the difference in square roots of two consecutive integers gets smaller as n grows?

I was playing around with python and I observed this: for i in range(0, 100): if i > 0: print((i ** 0.5) - ((i -1) **…
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Solve the equation without using square both sides

Solve the equation without using square both sides: $$(x+1)(2x^{3}-5)^{1/2}= 2x^{3}- 3x^{2}+x-2$$ I try to use Wolfram Alpha and here is the the answer: https://www.wolframalpha.com/input/?i=(x%2B1)+(2x%5E3-+5)%5E(1%2F2)%3D+2x%5E3-3x%5E2%2Bx-2 I…
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Square root question with ^3

I'm trying to write $(\sqrt{3}/\sqrt{6})^3$ to simplest form possible which should be $1/4\sqrt{2}$. This is what I tried: (√3/√6)^3 = (√3/√6 * √6/√6)^3 = (√18/6)^3 = √18^3/6^3 = √5832 / 216 =... I'm kinda stuck here and do not know what mathematics…
Iball
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Sum of reciprocal of sum of 3 cube roots

Simplify $$\frac{1}{\sqrt[3]1+\sqrt[3]2+\sqrt[3]4}+\frac{1}{\sqrt[3]4+\sqrt[3]6+\sqrt[3]9}+\frac{1}{\sqrt[3]9+\sqrt[3]{12}+\sqrt[3]{16}}$$ I have no idea how to do this. I tried using the idea of multiplying the conjugate to every term, but I…
QuIcKmAtHs
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Confused about square root

So i have this equation $$-\sqrt{C_1-y^2}=x+C_2$$ I want to get rid of radical by squaring both sides, the negative sign in front of the first term will become positive right? I know this is a silly question but i need to make sure, my background at…
johnny
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Simplifying cube square root

I just need some classification on simplifying this cube square root: $$\sqrt[3]{x^4}$$ Could you cancel the 4 with the 3 and end up with just $x%$ or would it be $(x^{4})^{1/3}$
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Why is $\sqrt[4]{4} = \sqrt{2}$

Why is $\sqrt[4]{4} = \sqrt{2}$ ? Sorry for the basic question, but having a bit of a hard time trying to understand this one.
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Radical w/ Variables Addition Simplification

I am working through some calculus problems and I am running into some trouble with simplifying a radical. I have a feeling there is an obvious rule for something like this that is simply eluding me at the moment, but here it is: $${(x-1)}^{5/3}…
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Even-even-odd rule with multiple terms in the radicand

I found one definition of the even-even-odd rule by the peeps at planetmath. They say that if a real variable to an even exponent is under a radical and the radical has an even index and, when the radical is eliminated, the resulting exponent on…
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How to simplify root over root expressions?

How is $\sqrt{9+2\sqrt6+2\sqrt8+2\sqrt{12}}$ simplified into $\sqrt2+\sqrt3+\sqrt4$ ?
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Reducing square root fractions without calculator

I am trying to figure out how to reduce simple square root fractions without a calculator. In my lecturer's notes, for instance, he reduces $1/\sqrt2$ by multiplying with $4/\sqrt2$. Following is his example and another example of him doing…
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Solving for unknown with square root as a term

I should be able to crank this out easily! Unfortunately not. So need some basic help here... I'm trying to determine parasitic inductance in an unknown inductor based on change of ringing frequency. By inserting a capacitance across the low-side…