At the top of the page, one of the tabs will be "History". Clicking on that will show who who made what changes when.
You can check who the last user was by clicking View history at the top of any article (next to the search bar). Note that the latest editor may be an IP address, that just means they didn't create an account.
Every Wikipedia article has a tab at the top that says "History". This tab lists every user who has edited that article. You may have to click through several pages of them!
Probably becouse noone wrote the article yet.
Wikipedia!
All Wikipedia pages are written by volunteers. By clicking on the article's history tab, you can see a list of everyone who contributed.
You will find several formulae in the Wikipedia article on "derivative".
Marion Crawford. There's a brief article in Wikipedia.
As of 2012, Wikipedia's article about catapults has been written by over a thousand mostly-anonymous contributors over the course of eleven years. You can see their usernames by clicking "View history" at the top of the page.
He is an Australian concert pianist. You can find a wikipedia article about him online.
You'll find a list in the Wikipedia article on "Nakshatra".
A good start to learn about lasers is to visit Wikipedia and read their article on lasers, their conception, and their mechanics. To find out more, scroll to the bottom of the article and click on the sources Wikipedia used to make their article to find more detailed and professional sources.
You can only create a Wikipedia article about people of note. If you are not famous in some way, the Wikipedia editors will remove your article.
Alton has its own website and an article on Wikipedia. There is also an Alton in New Hampshire, US, which also has its own website and Wikipedia article.
You can find an introduction to Stokes' Theorem in the corresponding Wikipedia article - as well as a short explanation that makes it seem reasonable. Perhaps you can find a proof under the links at the bottom of the Wikipedia article ("Further reading").