Look Ma, no integrals! (Posted on 2006-05-02)

	Submitted by Federico Kereki
Rating: 3.7500 (4 votes)
Solution:	(Hide)
The kid thought: if f=a+bx+cx²+dx³+..., then f²=a²+2abx+(2ac+b²)x²+(2ad+2bc)x³+... and f '=b+2cx+3dx²+4ex³+... Since f²/f '=1, both series must be equal, and therefore b=a², c=a³ and so on, so f= a+a²x+a³x²+...= a/(1-ax)= 1/(K-x) if K=1/a.

	Subject	Author	Date
	serious problem with solution	Bon	2006-07-23 16:10:44
	Worked it out	e.g.	2006-05-04 09:33:36
	A few more solutions	owl	2006-05-03 11:38:22
	re(3): My (cryptic, mysterious, sibylline) Way	owl	2006-05-03 08:52:39
	Combined Approach	Richard	2006-05-02 20:01:41
	re(3): My (cryptic, mysterious, sibylline) Way	Richard	2006-05-02 17:16:01
	re(2): My (cryptic, mysterious, sibylline) Way	Old Original Oskar!	2006-05-02 16:16:55
	re: My (cryptic, mysterious, sibylline) Way	Richard	2006-05-02 16:06:36
	My (cryptic, mysterious, sibylline) Way	Old Original Oskar!	2006-05-02 16:03:14
	re: Stupidity Tries	Richard	2006-05-02 15:57:50
	re(2): Observations and maybe solution	Richard	2006-05-02 15:52:45
	Stupidity Tries	tomarken	2006-05-02 15:45:43
	re: Observations and maybe solution	Federico Kereki	2006-05-02 15:41:30
	Observations and maybe solution	Richard	2006-05-02 14:08:20