Polynomial Division: Simplifying 3rd Roots in Denominator

AI Thread Summary
The discussion focuses on simplifying the expression with a cube root in the denominator. The original expression is \(\frac{ \sqrt[3]{25} + \sqrt[3]{5x} + \sqrt[3]{x^2} }{ \sqrt[3]{x} - \sqrt[3]{5} }\). A participant expresses frustration at not knowing how to eliminate the roots, indicating that traditional methods like using the conjugate or raising to the power of three aren't applicable. Another user suggests using the identity \(y^3 - a^3 = (y - a)(y^2 + ay + a^2)\) as a potential solution. This identity provides a pathway to simplify the expression effectively.
Hannisch
Messages
114
Reaction score
0
3rd roots in denominator

Homework Statement


\frac{ \sqrt[3]{25} + \sqrt[3]{5x} + \sqrt[3]{x^2} }{ \sqrt[3]{x} - \sqrt[3]{5} }

Rewrite the expression with no roots in the denominator and it being simplified as far as possible.

Homework Equations


The Attempt at a Solution


I'm.. stumped. Seriously. How on Earth do I get rid of them? I can't do the conjugate, I can't take the denominator to the power of three, I can't take it times (x3 + 53) and I'm out of ideas.Sorry about it being called Polynomial division, mishap on my behalf.
 
Last edited:
Physics news on Phys.org
Try to use the identity

y3-a3=(y-a)(y2+ay+a2)

ehild
 
Thank you! I'd never have figured that one out myself
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Back
Top