View Full Version : Slightly advanced math
SeeDRankLou
02-03-2009, 10:07 PM
I was in my linear algebra class, and I was taking notes about how to prove Holder's Inequality. There is this one part (noted in red), I don't know how I went from 1 to 2.
http://i47.photobucket.com/albums/f155/maddylouis/EoFF/whatdidido.jpg
How did I (or my professor) go from 1 to 2?
FFIX Choco Boy
02-10-2009, 03:16 AM
Remember Factoring polynomials? Same thing.
3x^2+7x+2=0
(3x^2+6x)+(x+2)=0
Then take out the GCF.
3x(x+2)+(x+2)=0
Reduce.
3x(x+2)=0
3x=0 x+2=0
x=0 x=-2
{-2, 0}
Tavrobel
02-10-2009, 04:37 AM
Remember Factoring polynomials? Same thing.
LOL no. First off, you factored your own example incorrectly.
3x<sup>2</sup> + 7x + 2 = 0 becomes
(3x+1)(x+2) = 0
x = -1/3 and -2
So that was just plain wrong. Also, I believe you have a severe misconception about what Linear Algebra is. It's Calculus level math, and SRL is working with matrices anyways (at least, that what it appears to be like). I have no idea how he got that 2 coefficient, but try working out the matrices that are given. Maybe a negative somewhere didn't cancel out? When SRL said "slightly," he may have sort of meant "very." It's a joke.
Aerith's Knight
02-10-2009, 03:36 PM
I think he used Young's inequality (http://en.wikipedia.org/wiki/Young%27s_inequality) to do that step.
It seems to follow that pattern, although I don't have the time to check it myself, sorry.
Good luck with the subject. I only scraped by with a 70% on Lineair Algebra myself. ^_^'
FFIX Choco Boy
02-10-2009, 09:01 PM
LOL no. First off, you factored your own example incorrectly.
3x<sup>2</sup> + 7x + 2 = 0 becomes
(3x+1)(x+2) = 0
x = -1/3 and -2
My mistake, wasn't paying much attention. But, yes, it seems to be the same basic process. I may be misreading some of his notes, because I don't pay a whole lot of attention anyways, but it seems at least very similar.
Hmm, just looked at it again, yup I looked at it wrong. Disregard and forget.
I Don't Need A Name
02-10-2009, 11:04 PM
why does american 'math' look so different to english maths?
Aerith's Knight
02-11-2009, 03:05 PM
Looks the same as my dutch lineair Algebra, so I think it's just you. :p
SeeDRankLou
02-13-2009, 09:38 AM
Yeah, it's Young's Inequality. My professor mentioned this in the next class, and then I found where I put this in my notes, it just wasn't given a name. Thanks everyone.
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