User talk:Ricardo sandoval

Welcome!

Hello, Ricardo sandoval, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or place {{helpme}} on your talk page and ask your question there. Again, welcome!

And don't forget, the edit summary is your friend. :) – Oleg Alexandrov (talk) 16:09, 13 February 2007 (UTC)[reply]

I replied on my talk regarding Euler's formula. Oleg Alexandrov (talk) 03:17, 28 March 2007 (UTC)[reply]

Request for edit summary[edit]

When editing an article on Wikipedia there is a small field labeled "Edit summary" under the main edit-box. It looks like this:

The text written here will appear on the Recent changes page, in the page revision history, on the diff page, and in the watchlists of users who are watching that article. See m:Help:Edit summary for full information on this feature.

Filling in the edit summary field greatly helps your fellow contributors in understanding what you changed, so please always fill in the edit summary field, especially for big edits or when you are making subtle but important changes, like changing dates or numbers. Thank you. – Oleg Alexandrov (talk) 02:37, 3 April 2007 (UTC)[reply]

Euler's formula and the helix[edit]

f(x) = e^xi is a function which takes arguments from the Real line (the variable "x") giving complex values, that is, points on the complex plane (f(x) = <a,bi>), right?

(Alternatively, one could write "e^x" taking arguments directly from the Imaginary line)

You're picturing a circle on the complex plane, but that's only the range of this function. To picture the actual function (Domain x Range, Real line x Complex plane) you have to add an extra dimension (from which it takes its arguments from, its Domain).

Then you have a helix.

I hope I've made myself clearer! —The preceding unsigned comment was added by 200.164.220.194 (talk) 04:55, 17 April 2007 (UTC).[reply]

I replied on my page...

"folding"[edit]

Your way of using the word "folding" in this edit is unfamiliar to me. I've changed it to the standard term "expanding", with a link to polynomial expansion.

Can you tell me where you came across this term? Is it computer-science jargon? Michael Hardy 00:12, 30 April 2007 (UTC)[reply]

I learned the term "folding" while tutoring pre-calculus courses here at Louisiana(I am a phd student) every body seems to understand it here. So I thought it was an usual American term. But now it strikes me as weird shouldn't it be "unfolding"?

I totally agree with your edit on the Brahmagupta-Fibonacci identity. I didn't know how to make references, Thank you for showing me.

I am actually from Brasil and back there they use the expressions like "opening", "distributing", or "expanding". Its funny to see how the original meanings relate to the mathematical usage. Do you now any other terms for "expanding"? Ricardo sandoval 04:21, 30 April 2007 (UTC)[reply]

That you learned it while tutoring arouses a suspicion in my mind: It may be a corruption of "foiling", a childish term used only by those whose method of learning mathematics relies heavily on memorization. "FOIL" is an acronym for "first, outer, inner, last", used to help people remember how to expand a product of two sums: multiply the two first terms of the two factors, then the two "outer" terms, then the two "inner" terms, then the two last terms, and add them. I learned that acronym when I was an undergraduate and I was tutoring students whose approach to mathematics relied on things like that. Michael Hardy 17:21, 30 April 2007 (UTC)[reply]

My god, I totally confused myself what they really use is "foiling", nice to know the origin, but I felt bad because there is no logic in it, even thought "expanding" is the most used term I really prefer "distributing" that comes from the distributivity law and also reflects better what you actually do. For me the geometric picture is the best explanation (Area of a bigger rectangle as the sum of the four smaller ones), so that students don't have to rely on such methods and actually understand what they are doing. Ricardo sandoval 23:08, 30 April 2007 (UTC)[reply]

Proof of Cosine Law using Power of Points[edit]

Responding to your request, I'll try to produce some simplified diagrams and proofs using Power of Points theorem. Interestingly the basic technique is described in a mathematical 'pre-amble' to the seminal work of Nicolaus Copernicus: "De Revolutionibus Orbium Coelestium".

I'll work in my user sandbox and then post here so you can approve/disapprove the suggested changes as you see fit.

Neil Parker (talk) 18:35, 14 December 2007 (UTC)[reply]

FAR Trigonometric functions[edit]

Trigonometric functions has been nominated for a featured article review. Articles are typically reviewed for two weeks. Please leave your comments and help us to return the article to featured quality. If concerns are not addressed during the review period, articles are moved onto the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Remove" the article from featured status. The instructions for the review process are here. Reviewers' concerns are here.--Ioannes Pragensis (talk) 12:40, 12 June 2008 (UTC)[reply]

ArbCom elections are now open![edit]

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 16:03, 23 November 2015 (UTC)[reply]