Return Styles: Pseud0ch, Terminal, Valhalla, NES, Geocities, Blue Moon. Entire thread

lol math competition

Name: Anonymous 2008-03-27 21:26

Okay, can't do these two.

Prove sum(k=1,n){arctan(1/(1+k+k^2))} = arctan(n/(n+2))

Show integral(0,infinity) e^{(x^2 + x^-2)/4} = sqrt(pi/e)

Name: Anonymous 2008-03-27 23:52

2nd one sounds incorrect. x^2 + x^-2 > x^2 for all real non-zero x, and integral(0,infinity) e^(x^2/4) = +inf. Ergo integral(0,infinity) e^((x^2 + x^-2)/4) = +inf.

For the first, use arctan(a) + arctan(b) = arctan((a+b)/(1-ab)).

Newer Posts
Don't change these.
Name: Email:
Entire Thread Thread List