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%I #14 Jun 24 2014 00:36:52
%S 2,8,8,8,3,6,5,7,9,7,5,1,3,6,4,0,1,3,7,5,4,3,1,2,1,7,4,0,5,5,0,0,9,2,
%T 3,1,9,8,4,1,5,2,5,9,9,2,9,5,9,0,1,0,2,3,8,4,7,2,8,7,2,8,1,0,0,2,8,7,
%U 3,7,2,0,6,5,6,4,4,6,7,0,2,6,0,8,0,6,9,8,9,5,5,6,5,8,7,4,0,9,6,7,6,9,4,5,3
%N Decimal expansion of the solid angle in steradians (sr) subtended by a cone with the polar angle of 1 radian (rad).
%C Given a right circular cone with polar angle theta, the solid angle it subtends is 2*Pi(1-cos(theta)). Not to be confused with the area, in steradians, of a spherical square with the side theta (see A231986).
%H Stanislav Sykora, <a href="/A243596/b243596.txt">Table of n, a(n) for n = 1..2000</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Solid_angle">Solid angle</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Steradian">Steradian</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Cone">Cone</a>
%F 2*Pi*(1-cos(1)) = 4*Pi*A243597.
%e 2.8883657975136401375431217405500923198415259929590102...
%t RealDigits[2 Pi (1 - Cos[1]), 10, 111][[1]] (* _Robert G. Wilson v_, Jun 12 2014 *)
%o (PARI) 2*Pi*(1-cos(1))
%Y Cf. A231986, A243597 (fraction of full solid angle).
%K nonn,cons,easy
%O 1,1
%A _Stanislav Sykora_, Jun 07 2014
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