Rewrite the radical as a rational exponent. the cube root of 2 to the seventh power
\[\huge x ^{m/n} = \sqrt[n]{x^m} = (\sqrt[n]{x})^m\]
That's it iambatman just said everything I was about to say. Use that formula and you will be able to get an answer.
so 2 7/3 ?
So how do we make roots as exponents? First off if you have something like \[\LARGE (n^3)^2=(n^3)(n^3)=(n*n*n)*(n*n*n)=n^6\] That tells us, ahh! It looks like the rule is to multiply exponents if they're something exponentiated raised to an exponent. So now we look at \[\LARGE \sqrt{x}^2=x^1\] So it looks like the x^2 is cancelled out by the square root to equal 1. This is just like the last case, so it must mean that \[\Large \sqrt{x}=x^{1/2}\] And this makes sense that it will be true for other roots too. Cube root should cancel out with the cube to be 1, so that should also be 1/3 power for cube root.
\[2^{7/3}\]
and to do this reversed? Rewrite the rational exponent as a radical. 5 to the 3 over 4 power, to the 2 over 3 power
how would I do that?
@WordGEEK @iambatman @Kainui
(53/4) 2/3
What are you trying to ask now?
what would (53/4)2/3 be as a radical ?
\(\Large (5^{ \frac 34})^ \frac 23 \) ?
yes^ :)
Since \(\Large (x^m)^n = x^{mn}\) Multiply the exponents first. What do you get?
6?
\(\Large \frac 34 * \frac 23\) = ?
1/2 ?
Yup good it equals 1/2 so now just apply the formula that iambatman posted.
Yes. \(\Large x^{\frac 12} = \sqrt{x}\). Therefore, \(\Large 5^{\frac 12}\) = ?
2\[\sqrt[2]{5}\]
and the one on the outside ?
I don't think that's right
Yes. But 2 is a special case where \(\Large \sqrt [2]{5} = \sqrt{5}\) Both mean the same. Square root 5 or just radical 5. \(\Large (5^{ \frac 34})^ \frac 23 = 5^{\frac 34 * \frac 23} = 5^\frac 12 = \sqrt {5}\)
oh okay! now it makes sense! that's one of the answer options. thank you! :)
You are welcome.
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