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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is 0.77777778 the same as 0.8 ? ( Square root problem )

I have holes in my math because I didn't pay attention when I was a kid.( so please explain in detail if possible <3 ) While relearning everything I found my self stuck not understanding how this works : $$\sqrt{\frac{49}{81}}$$ my steps to solve…
Moath
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Rationalizing radical expressions

$\sqrt [ 3 ]{\frac{3}{4} }$ is the expression. What i did was change it to an equivalent fraction $({\sqrt [ 3 ]{\frac{6}{8} }=\frac{\sqrt [ 3 ]{ 6}}{2} } )$. But i think it isn't right. Please help me.
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simplifying radicals and fractional numbers

$$\frac{a}{a-\sqrt{a^2-16}}$$ is the expression. I am not sure if i answered it right but please help me do this.
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Converting root to exponent

I am new to Math and learning Root, I came across two different Root and simply them. As Roots are the inverse operation of Exponents. I want to express the output in exponent for practice purposes. I am confused with the output of second question.…
Jitender
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Square root of increasing Exponents of 2

Question: Evaluate $$2\sqrt{2^3\sqrt{2^4\sqrt{2^5\sqrt{2...}}}}$$ I've been trying to look for a pattern in pulling out parts of the exponents (ex. taking a $2^2$ from the $2^3$ in the first square root). I've also been trying to see if I could so…
user978757
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Continued square roots sequence

Apologies if this has been asked before, I could not find it. Define a sequence $a_n$ by $a_0 = 1$ and $a_n = 1+\sqrt{a_{n-1}}.$ Find the closed form, if it exists, of $a_n.$ So I can see this is just continued square roots. I know how to…
user797346
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Optimal way to pick the starting $x$ when computing the square root with the Babylonian method

I was reading the example given in the Wikipedia article for the Babylonian method of computing the square root, and I wondered why did they set the starting $x_0$ to 600: To calculate $\sqrt S$, where S = 125348, to six significant figures, use…
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Help with inverse proportions

The value of $y$ varies inversely as $\sqrt x$ and when $x=24$, $y=15$. What is $x$ when $y=3$? I'm having trouble on this and I don't get why it's not $\frac{2\sqrt6\cdot15}{3}=10\sqrt6$? Am I misinterpreting the problem? This is how I learned…
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Shifting decimals and square roots (eg, $\sqrt{64}$ vs $\sqrt{0.64}$ vs $\sqrt{6.4}$)

The square root of $64$ is $8$. If the decimal of $64$ is shifted by two places to the left (i.e. $0.64$), then the decimal of the answer is shifted by one place to the left (i.e. $0.8$), so the square root of $0.64$ is $0.8$. Is there any…
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what are the rules regarding $x,a,b$ for this expression to be true: $(x^a)^b = (x^b)^a$ (i am considering only for when $a,b$ are real)?

in particular i am asking for the case when one of the powers $a$ or $b$ is a fraction. in such a case, i believe the maths expression then may be ambiguous, as when you do to the power of a fraction, it's not clear if the required answer is the…
Randor
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How can I solve this integer part question?

I am trying to understand this problem but my textbook does not offer a good explanation,it asks what the integer part of the square root is. $\sqrt{n^2+6n}$ , $n \in N$*
ROBOTICS
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square root and sign

My question is very very basic but, for the life of me, I'm confused for whatever reason. I know that if $x^2 = 5 $ then +$\sqrt{5}$ and $-\sqrt{5}$ are the solutions for $x$. The reason, as I understand it, is that, in a function, $x$ can have two…
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How do I solve $\sqrt{x-\sqrt{x-\sqrt{x...}}}=9 \Rightarrow x=?$

$\sqrt{x-\sqrt{x-\sqrt{x...}}}=9 \Rightarrow x=?$ I'm preparing for exam. This question comes from metropol mat1 testbook.
black
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Why does $\sqrt{x\sqrt{x}}$ equal $x^{3/4}$ instead of $x^{1/4}$?

When I try to solve the equation, I get $x^{1/4}$ since the two roots share the same index and exponent, which means that I ought to be able to multiply across. Instead, the solution in the textbook is as follows. $$\left (xx^{1/2} \right…
Nathaniel
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How to use radical rules for this?

$$\sqrt{3+\sqrt{2\sqrt{7}+1}}-\sqrt{3-\sqrt{2\sqrt{7}+1}}=?$$ Which one of the following is a true answer and why? $\sqrt{7}-7$ $1-\sqrt{7}$ $\sqrt{7}-1$ $\sqrt{7}$ $\sqrt{7}+7$