My translation of Lagrange's 1772 paper "Essai sur le Probleme des Trois
Corps" is at http://www.merlyn.demon.co.uk/essai-3c.htm. What
Lagrange wrote is rather different from what he is commonly alleged to
have written. It is quite easy to see what he did, if the equations are
all taken on trust.

http://www.merlyn.demon.co.uk/gravity4.htm#x2 gives a new, simple,
proof that L4 and L5 exist at the equilateral locations.

--
(c) John Stockton, nr London, UK. Turnpike v6.05 MIME.
Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.