OFFSET
0,1
COMMENTS
Given a square with a side measuring 2 units, having a circle with a radius of 2 units centered on one of its corners, and another circle also with a radius of 2 units centered on the most distant corner from the one on which the first circle is centered, there are two "zones" within the square that overlap with the area of only one of the circles. This number gives the area of either zone. - Alonso del Arte, Aug 01 2012
Area between a circle of radius 1 and the circumscribed square. - Omar E. Pol, Aug 02 2012
Perimeter of the unit square minus the circumference of its incircle. - Jonathan Sondow, Nov 23 2017
LINKS
FORMULA
4 - Pi = (-1)(Pi - 4) = (-1)*Sum_{n >= 1} (4*(-1)^n/(2*n + 1)) = (-1)*arcsin(sin 4). - Alonso del Arte, Aug 01 2012
Equals Integral_{x=0..Pi} cos(x)^2/(1 + sin(x))^2 dx. - Amiram Eldar, Aug 21 2020
Equals Integral_{x=0..4} sqrt(x)/(4+x) dx. - Andy Nicol, Mar 23 2024
EXAMPLE
0.8584073464102067615373566167204971158...
MATHEMATICA
RealDigits[4 - Pi, 10, 100][[1]] (* Alonso del Arte, Aug 01 2012 *)
PROG
(PARI) 4-Pi
CROSSREFS
KEYWORD
AUTHOR
Omar E. Pol, Jan 25 2009
STATUS
approved