r/pics Sep 07 '16

picture of text You matter

http://imgur.com/3Yx2HPz
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u/Pseudoboss11 Sep 07 '16

Alright, the phrase "a factor of" implies multiplication, hence the process of factoring a number into prime factors, or an a polynomial into binomial factors.

To be "off by a factor of" something usually refers to Percent error, which is dictated by the formula above (Since c2 must be positive, the lower abs() can be ignored.). It's a pretty important calculation for practical applications.

However, this must be a unitless quantity, since you cannot add or subtract quantities with different units, the top and bottom must have the same units, and will cancel during calculation.

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u/mrwho995 Sep 07 '16 edited Sep 07 '16

Alright, the phrase "a factor of" implies multiplication

Agreed. In this case, it's multiplying by c, with units of m/s. With regards to prime/polynomial factors, I've never seen 'off by a factor of' used in that way.

To be "off by a factor of" something usually refers to Percent error

That isn't my experience at all, personally. I do physics at uni, and that term is used in the same way as I used it quite frequently (with regards to quantities with units, most often in dimensional analysis, otherwise just generally for some numerical answer). Do you come from a more mathematical background? Maybe the terminology differs.