- #1

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(excuse the clutter, for I do not know how to use Latex)

cube root ( -125 m^-4 n^5 )

I fully simplify this to:

-5n/m * cube root (n^2 / m )

The answer is incorrect, wtf am I missing?

- Thread starter uranium_235
- Start date

- #1

- 36

- 0

(excuse the clutter, for I do not know how to use Latex)

cube root ( -125 m^-4 n^5 )

I fully simplify this to:

-5n/m * cube root (n^2 / m )

The answer is incorrect, wtf am I missing?

- #2

- 574

- 2

I'm not sure how they want you to simplify this, but remember the following:

[tex]\sqrt[x]{y^{z}}=y^{\frac{z}{x}}[/tex]

- #3

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The correct answer is:

-5n/m^2 * cube root(m^2 n^2)

I can not figure out how thay came to that answer.

- #4

- 574

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- #5

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Thank you. I was a nervous wreck thinking I had missed something in class, or could not understand the question.

- #6

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- #7

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[tex]\frac{-5n}{m}\sqrt[3]{\frac{n^2} {m}}[/tex]

Now, multiply the whole problem by 1--in disguise though:

[tex](\frac{m}{m})\frac{-5n}{m}\sqrt[3]{\frac{n^2} {m}}[/tex]

remember, m divided by m is 1.

Now, move the m in the numerator into the radical by saying: [itex]m=\sqrt[3]{m^3}[/itex]

Thus you have:

[tex]\frac{-5n}{m^2}\sqrt[3]{m^3\frac{n^2} {m}}[/tex]

and of course the m in the denominator of the radical cancels oy leaving you with the correct answer.

[tex]\frac{-5n}{m^2}\sqrt[3]{m^2n^2}[/tex]

This is what you're "supposed" to do when you have a radical in the denominator. Will you do this all the time? No. One example of not bothering to do this is [itex]\cos 45^\circ=\frac{1}{\sqrt{2}}[/itex]

You'll see these trig values written with the radical in the denominator quite often because the radical can be cancel later on or the required answer will be a decimal approximation.

Hope this helped.

- #8

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- #9

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It is good to practise LaTeX. Many maths symbols and Greek characters can be written :uranium_235 said:(excuse the clutter, for I do not know how to use Latex)

[tex]\tau\upsilon\rho\nu\beta\alpha\chi\kappa\sigma\iota\gamma\alpha\nu\delta\epsilon\lambda\iota\mu\iota\nu\alpha\tau\epsilon\tau\eta\epsilon\rho\epsilon\pi\epsilon\alpha\tau\iota\nu\gamma\kappa\epsilon\psi[/tex]

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