View Single Post
Old 06-14-2007   #15 (permalink)
Jesus
Commentator
 
Join Date: Jun 2007
Posts: 52
Default Re: Math Problem Game

Quote:
Originally Posted by qtwerp View Post

x²y'' + 3xy' + 2y = 0

[---]

No, it's a "simple" Cauchy-Euler differential equation. y' is the first derivative of y and y'', the second derivative. It should be possible without having to write down a lot of work. It's not that difficult if you've done them before.

Here's the big hint for it: y = x^m
Thanks for the hint

m ^2 x^m + 3 m x^m + 2 x^m = 0

(x != 0)

m^2 + 3m + 2 = 0

m = -1, m = -2

--------------------------

How about:

Prove:

\sum_{n = 1}^{\infty} 1/n^s = 0 \iff \Real(s) = 1/2 where s != {-2,-4,-6...}


Nahh... just messing with you. Just state the name of the problem
Jesus is offline   Reply With Quote