The professor wrote the differential equation f²/f'=1 on the blackboard, and asked the students to solve it.

Everybody started working with the usual methods, except for a kid at the back of the class, who happened to have skipped that material, but was very bright.

Can you solve this equation without any integration?

(In reply to re: My (cryptic, mysterious, sibylline) Way by Richard)

Giving details is very un-cryptic, un-mysterious, and un-sibylline, but anyway... I assumed there had to be a MacLaurin series for f(x), and then equated the series for f' and f², which allowed me to find the series coefficients, which produced a well known result: f(x)= 1/(C-x) for constant C.

Posted by Old Original Oskar! on 2006-05-02 16:16:55