need help rationalizing a cube root

greenfish13

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May 7, 2013
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Hi,

This is my first post here. My question is how to solve this:

1- ________1_________
cuberoot(R^(2)))

I appreciate any help on this, thank you.
 
Hi,

This is my first post here. My question is how to solve this:

1- ________1_________
cuberoot(R^(2)))

I appreciate any help on this, thank you.
Is this the problem:

\(\displaystyle Rationalize\ 1 - \dfrac{1}{\sqrt[3]{r^2}}?\)

What is meant by rationalizing an expression?

If you understand what the term means, such problems are not super-difficult. If you do not understand what is being asked, the problem seems impossible.

Take a look at. http://www.wtamu.edu/academic/anns/mps/math/mathlab/int_algebra/int_alg_tut41_rationalize.htm See if that helps. If not, please show us your work up to where you get stuck.
 
Last edited:
Is this the problem:

\(\displaystyle Rationalize\ 1 - \dfrac{1}{\sqrt[3]{r^2}}?\)

What is meant by rationalizing an expression?

If you understand what the term means, such problems are not super-difficult. If you do not understand what is being asked, the problem seems impossible.

Take a look at. http://www.wtamu.edu/academic/anns/mps/math/mathlab/int_algebra/int_alg_tut41_rationalize.htm See if that helps. If not, please show us your work up to where you get stuck.

Yes Jeff what you wrote is exactly what I intended to say, sorry I don't know how to make the cube root sign and everything else that you did. Posted below is the most up to date work that I have done to get the answer:


1 - \dfrac{1}{\sqrt[3]{r^2}}?[/tex] * cuberoot R^2*cuberootR^2= cuberootR^4=cuberootR^4-1(R/R)= cuberootR^4-R
_________________________________cuberootR^2*cuberootR^2 cuberootR^8=____R_________________R

I used two lines to indicate the numerator and the denominator. I hope this is makes sense. Please let me know if it doesn't. Thank you.
 
1 - \dfrac{1}{\sqrt[3]{r^2}}?[/tex] * cuberoot R^2*cuberootR^2= cuberootR^4=cuberootR^4-1(R/R)= cuberootR^4-R
_________________________________cuberootR^2*cuberootR^2 cuberootR^8=____R_________________R

I hope this is makes sense. Please let me know if it doesn't.
I can't make heads or tails of this. If you don't care to use the LaTeX formatting available here, then please use standard web-safe formatting, as illustrated here. Thank you! ;)
 
Yes Jeff what you wrote is exactly what I intended to say, sorry I don't know how to make the cube root sign and everything else that you did. Posted below is the most up to date work that I have done to get the answer:


1 - \dfrac{1}{\sqrt[3]{r^2}}?[/tex] * cuberoot R^2*cuberootR^2= cuberootR^4=cuberootR^4-1(R/R)= cuberootR^4-R
_________________________________cuberootR^2*cuberootR^2 cuberootR^8=____R_________________R

I used two lines to indicate the numerator and the denominator. I hope this is makes sense. Please let me know if it doesn't. Thank you.
Please do NOT try to show fractions using the vertical notation unless you can use LaTeX. Otherwise, use the horizontal notation and PEMDAS. Unless you intend to ask many questions, it is probably not worth your while to learn LaTeX.

(a + b) / c = \(\displaystyle \dfrac{a + b}{c}\)

a + b/c = \(\displaystyle a + \dfrac{b}{c}.\)

As for roots, use ^ to indicate exponentiation and fractional exponents to represent roots: a^(1/3) = \(\displaystyle \sqrt[3]{a}.\)

I THINK that this is what you did.

\(\displaystyle 1 - \dfrac{1}{\sqrt[3]{r^2}} = 1 - \left(\dfrac{1}{\sqrt[3]{r^2}} * 1 * 1\right) = 1 - \left(\dfrac{1}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^2}}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^2}}{\sqrt[3]{r^2}}\right).\)

This first step is correct. When you multiply an expression by 1, you do not change the value of the expression.

After this you slip off the rails (if, that is, I am following you).

\(\displaystyle 1 - \left(\dfrac{1}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^2}}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^2}}{\sqrt[3]{r^2}}\right)\ DOES\ NOT\ EQUAL\ \dfrac{\sqrt[3]{r^4} - r}{r}.\)

\(\displaystyle 1 - \left(\dfrac{1}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^2}}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^2}}{\sqrt[3]{r^2}}\right) = 1 - \left(\dfrac{1}{\sqrt[3]{r^2}} * \dfrac{\sqrt[3]{r^4}}{\sqrt[3]{r^4}}\right) = 1 - \dfrac{\sqrt[3]{r^4}}{\sqrt[3]{r^6}}= 1 - \dfrac{\sqrt[3]{r^4}}{r^2}.\)

There are still a few steps left to go. What do you get?
 
Hi,

This is my first post here. My question is how to solve this:

1- ________1_________
cuberoot(R^(2)))

I appreciate any help on this, thank you.


greenfish,

also, make sure if the problem is using the upper case, "R," as you typed it here,
or the lower case, "r."

I state that because JeffM included the "r" as the variable in his clarification
question and work.

"R" and "r" are not interchangeable.
 
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