Talk:Rate (mathematics)

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WikiProject Time assessment rating comment[edit]

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Yamara 23:10, 5 May 2008 (UTC)

Discussion[edit]

hello i want to see a table of reactivity --193.195.198.254

You should ask for this on Talk:Reactivity. --Toby Bartels 15:35, 2 March 2007 (UTC)

Definition[edit]

I do not see that 'meters' and 'seconds' are the same unit, what would in fact be a 'ratio'. That definition differs completely from that e.g. in the Oxford Dictionary.HJJHolm (talk) 13:43, 15 July 2008 (UTC)

Your point regarding that the two measurements is taken. They can be the same unit or different units.+mt 14:33, 15 July 2008 (UTC)

Rate is all about time[edit]

Rate is a measure of something over time. And the article should say that. Re-write. Paul Beardsell (talk) 07:23, 1 March 2009 (UTC)

Your claim is incorrect. A rate is simply a ratio of something per something used in a particular context. The denominator is often time, but it doesn't need to be. Examples of rates that are not "something over time" include exchange rate, inflation rate, unemployment rate. +mt 17:59, 1 March 2009 (UTC)

Inflation rate is the change in prices per unit time. The rate of change is always (I contend) per unit time. Where you are correct is when "rate" is used instead of "ratio", often incorrectly. Unemployment rate is a proportion and really unemployment ratio. The growth in unemployment is unemployment rate. Like it or not, in maths a "ratio" is a fraction or a proportion and is often dimensionless. "Rate" is usually change per unit time. Paul Beardsell (talk) 23:13, 1 March 2009 (UTC)

English is imprecise. And there is room for a disambiguation page and, what do you know, there is one: See rate. But the name of this article is "Rate (mathmatics)". Reverting. Please do not revert back to what I think is a poorly written and imprecise version of the article. Thanks. Paul Beardsell (talk) 23:13, 1 March 2009 (UTC)

We agree that this is a mathematics article, but variables and dimensions are usually treated generically in math, so this doesn't help your case. My calculus textbook (Adams, Robert A. (1995). Calculus: A Complete Course (3rd ed.). Addison-Wesley Publishers Ltd. pp. 129,135. ISBN 0-201-82823-5. ) has all sorts of examples that describe rates that are not "per time", such as "the rate of change of the area of a circle with respect to the radius" in one example or "the rate of change in gravitational force with respect to distance from Earth", etc. Yes, this book also provides many "per time" examples as well. Search for "rate" in derivative and evaluate the context in which it is used. The formal definition of the "rate of change" in my textbook (p.129), (added to front page) does not assume "per time" anywhere since it is an unnecessary limitation. In an applied use, a gradient rarely has rates in units "per time" (usually it is a spatial dimension). Still not convinced? Look for the definition of "rate" at these links: [1], [2], [3], [4], [5]. I'm all for improvements in this article and I'll agree that the prior version was mismanaged, but you completely modified the definition to what you thought it was, which is why I revered your work (also, consider the use of a spell-checker). The content of your edits are not wrong, but your assumption of always "per time" is not correct and is not supported by references. Terms like "unemployment rate", "tax rate", "exchange rate" are not wrong, since this terminology sits fine with the formal definition that I'm showing you. +mt 05:41, 2 March 2009 (UTC)
You're right. Sorry to be disruptive. But the default "per unit" is "per unit time". If you don't say then the rate of somthing is the rate per unit time. Notice also the project template (how I hate those). Paul Beardsell (talk) 08:27, 2 March 2009 (UTC)