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Mathematics 17 Online
OpenStudy (mojutmnt):

Someone please explain Rational Exponents, (please be descriptive)

OpenStudy (anonymous):

\[x^{\frac{a}{b}} = \sqrt[b]{a}\]

OpenStudy (anonymous):

\[b \neq 0\]

OpenStudy (mojutmnt):

I want to find out an easy way to simplify working out rational exponents given an exponent within the root of a number (Example: 4^sqrt300 = n). Too many sources show how exponents from roots can be broken into fractional exponents of the rooted number, but what's the work needed to just get the answer????

OpenStudy (anonymous):

@JoãoVitorMC That is very very wrong.

OpenStudy (anonymous):

@MOJUTMNT You want a method of calculating rational numbers?

OpenStudy (mojutmnt):

Yes. ^~^

OpenStudy (anonymous):

yes sorry i missed the "x" \[x^{\frac{a}{b}} = \sqrt[b]{x^a}\]

OpenStudy (mojutmnt):

Through roots.

OpenStudy (anonymous):

Okay, the first thing you should do is simplify the fraction to the simplest form to make your life easy. Then do this: \[ c^{a/b} = (c^a)^{1/b} \]Now, to make things easier we'll say \(x = c^a\) and use \(x\) from here on out. I suppose it wouldn't be hard for you to find \(x\), right?

OpenStudy (anonymous):

We want to find \(x^{1/b}\)

OpenStudy (anonymous):

Do you understand how it doesn't really matter what the numerator is, that the hard part is really just in the denominator?

OpenStudy (mojutmnt):

Before you continue, this is done through square roots.

OpenStudy (anonymous):

Can you give an example of what you mean?

OpenStudy (mojutmnt):

For instance, I mean like the square root of 300 with an exponent of 4 next to the root.

OpenStudy (anonymous):

\[ \sqrt{300^4} \]?

OpenStudy (mojutmnt):

With the 4 to the left of the square root as an exponent.

OpenStudy (anonymous):

\[ \sqrt[4]{300} \]?

OpenStudy (mojutmnt):

Yes.

OpenStudy (anonymous):

Do you know how to factor out a number?

OpenStudy (mojutmnt):

Do you mean by finding the highest number divisible?

OpenStudy (anonymous):

Factorizing a number... Here's an example: |dw:1363575345150:dw|

OpenStudy (mojutmnt):

So I have to find the lowest number divisible, and then break it down by repeating that same process?

OpenStudy (anonymous):

You want to divide out any prime numbers, until all that is left is a bunch of prime numbers.

OpenStudy (mojutmnt):

This is perfect, can I show you an example of a problem I have?

OpenStudy (mojutmnt):

OpenStudy (agent0smith):

|dw:1363575958150:dw|

OpenStudy (mojutmnt):

Where does the exponent of 4 come into play?

OpenStudy (agent0smith):

There is no exponent of 4, that's multiplication\[135 = 5 *3 *3 *3 = 5* 3^3 \] so now your \[\large 4 * \sqrt[3]{135} \] \[\huge 4 * \sqrt[3]{5*3^3}\]

OpenStudy (agent0smith):

\[\large 4 * \sqrt[3]{5*3^3} = 4 * \sqrt[3]{5}*\sqrt[3]{3^3}\]

OpenStudy (mojutmnt):

No, the four is an exponent... just like the 3 is in the new problem you just created.

OpenStudy (agent0smith):

I didn't create a problem... i was using your image: http://assets.openstudy.com/updates/attachments/51467a27e4b04cdfc582af15-mojutmnt-1363575901148-rationalexponent.png

OpenStudy (mojutmnt):

My fault. That question was meant for the previous problem.

OpenStudy (mojutmnt):

Before we continue can you show me how the exponent of 4 was used in the previous problem.

OpenStudy (fibonaccichick666):

maybe a helpful hint, exponents can be written multiple ways ex. these are equivalent \[\sqrt[4]{x}=x^{\frac{ 1 }{ 4 }}\]

OpenStudy (fibonaccichick666):

was that the square root to fraction, you were looking for?

OpenStudy (agent0smith):

Oops, my bad, 300 = 3*2*2*5*5 NOT 2*2*5*5*5 If you understand up to here, then... \[\large (3*2^2*5^2)^{\frac{ 1 }{ 4 }} = 3^{\frac{ 1 }{4 }} (2^2)^{\frac{ 1 }{ 4 }} * (5^2)^{\frac{ 1 }{ 4}}\]

OpenStudy (mojutmnt):

Thank you very much for that answer. Thank you all for being descriptive. All I needed was for someone to spell it out for me.

OpenStudy (mojutmnt):

@agent0smith is that the final answer?

OpenStudy (agent0smith):

Not yet. Can you simplify it from there? Note that \[\huge (a^b)^c = a ^{b*c}\] try using it on this: \[\large 3^{\frac{ 1 }{4 }} *(2^2)^{\frac{ 1 }{ 4 }} * (5^2)^{\frac{ 1 }{ 4}}\]

OpenStudy (mojutmnt):

Yes I can, thank you. Now back to the next question I will post a new screen shot.

OpenStudy (mojutmnt):

OpenStudy (agent0smith):

This was Q2:\[ \large 4 * \sqrt[3]{5*3^3} = 4 * \sqrt[3]{5}*\sqrt[3]{3^3} \] \[\large 4 * \sqrt[3]{5}*({3^3})^{\frac{ 1 }{3 }}\]

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