Math... help please?? *scratches head* I need it now, I have an exam!

lucky_cricket • 19 December 2012 at 8:12 PM

Could someone please explain to me the rational root theorem? I just need to know what the point of it is, and how it works.
I can't seem to find a good explanation on the internet.

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Deleted • 19 December 2012 at 8:14 PM

@lucky_cricket

Ok. I HAVE NO IDEA WHAT IN THE HECK THAT IS. Although, I do do 7th grade math....although im in 4th grade....but, BEST OF LUCK!

meixiaotian • 19 December 2012 at 8:14 PM

@rushingwater_side Really?

lucky_cricket • 19 December 2012 at 8:15 PM

@rushingwater_side Thanks!! I do math a couple years ahead too, always enriched.

angelbones • 19 December 2012 at 8:17 PM

@lucky_cricket
Ahh, I'm so sorry but I've never heard of that in my life :/. Mostly because I live in New Zealand, so the schooling system is different. And I'm only in what's equivalent to the 10th grade in the states, so I really have no clue. I looked it up on wikipedia and it looks rather complex, so good luck!!

Deleted • 19 December 2012 at 8:19 PM

@meixiaotian

Yup. 😃

4 . 3
- - -
5 . 4

(four-fifths divided by three-fourths)

4 4
- x -
5 3

=

16 1
- or 1 -
15 15

(One and one-fifteenth is the answer to four-fifths divided by three-fourths.)

lucky_cricket • 19 December 2012 at 8:19 PM

@angelbones I tried wikipedia too, but it made no sense to me. I am in grade 9, but do an enriched course. I missed two weeks sick, and it's the only thing I am clueless on.

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Zac • 19 December 2012 at 10:39 PM

Basically, the point of the Rational Root Theorem is to find the roots of polynomials (meaning, the values of x where the polynomial is 0) without using polynomial division.

I'd check out this site if you have questions. From a glance, it looks like it does a decent job.

http://www.trans4mind.com/personal_development/mathematics/polynomials/rationalRootTheorem.htm

In a nutshell, you're looking at the first and last coefficients and finding their factors. (call each factor p and q) The list of all possible roots can be found by dividing every p by every q. So all you have to do is test the different combinations.

The Wikipedia entry isn't going to help you much since it's more about the derivation of the theorem. I doubt you'll have to worry about the Taylor polynomials and power series theorems at this point. 😋