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0 pointsmraleph8y ago0 comments

but I am not talking about the percentage increase I am talking about increase "by a factor of X" that is X = B/A.

See: https://ell.stackexchange.com/a/52747

Maybe my problem is that I am missing "by".

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IncRnd8y ago

You are exactly talking about percentages.

B/A is the percentage of the new value relative to the old.

(B-A)/A is the percentage of the increase of the value.

This is algebra not English.

1) You start out with one rock. 2) You add another rock, getting a pile of two rocks. 3) The rock pile size is now 200% of the original size. But, the increase of the rock pile size is 100%. 4) According to the rules of algebra, 100% = 1. In this case 100% = 1 rock, since the unit under discussion is rocks.

neurotrace8y ago

They absolutely are not talking about percentages. They're talking about factors. A factor is a term in a multiplication. In standard US English, increasing something by a factor means to multiply it by that number. Even the GMAT uses that phrase in that way. You absolutely can split hairs on this and the phrasing can be confusing but it is absolutely understood that "increased by a factor of 4" means to multiply by 4. If one was talking in terms of percentages, they would say something like "increased by 300%".

IncRnd8y ago

>* increasing something by a factor means to multiply it by that number*

That's absolutely wrong... When you multiply something you scale it by a factor. When you add to something you increase it.

1) 4A is 400% of A.

2) 4A in an increase of 300%.

3) 4A is an increase of 3A.

4) 4A is an increase of a factor of 3.

In the most charitable interpretation you are confusing the terms of exponential growth with linear scaling and misapplying from one to the other. A growth factor is not the same as an increase in a factor.

neurotrace8y ago

Go ahead and tell that to everyone who has been using that phrase to mean what I describe. I seriously searched for a single case of someone using the phrase in the manner you're insisting is correct and came up empty. Instead, I found a large number of resources backing up what I and OP have been stating. Even many professional mathematicians acknowledge the ambiguity but agree that the phrase means to multiply. You may disagree with how the phrase came to be but it clearly has been taken to mean to multiply.

https://www.beatthegmat.com/word-translation-when-x-increase...

https://www.quora.com/Mathematics-What-does-it-mean-to-incre...

https://www.macmillandictionary.com/us/dictionary/american/b...

http://mathforum.org/library/drmath/view/74439.html

https://ell.stackexchange.com/questions/52706/what-does-redu...

https://www.physics.uoguelph.ca/tutorials/exp/factor.html

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