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A231981 Decimal expansion of one steradian (sr) expressed in square degrees. 7

%I #21 Aug 21 2023 12:48:40

%S 3,2,8,2,8,0,6,3,5,0,0,1,1,7,4,3,7,9,4,7,8,1,6,9,4,6,0,7,9,9,5,1,7,5,

%T 5,0,0,5,0,1,2,2,4,2,9,9,3,8,0,7,8,8,1,8,2,5,9,7,7,3,2,6,3,3,3,7,1,2,

%U 0,9,1,1,9,1,7,6,4,2,8,2,9,4,5,9,5,1,8,0,4,7,5,1,9,0,1,4,7,5,3,8,6,8,1,3,6

%N Decimal expansion of one steradian (sr) expressed in square degrees.

%C This is the conversion ratio between two solid-angle measures: steradians and square degrees, applicable to integration infinitesimals. The square degree must not be confused with a finite spherical square having one degree side (see A231983, A231984, A231985), just as one steradian must not be confused with the solid angle covered by a spherical square with a side arc-length of one radian (see A231986, A231987).

%C Equals also full solid angle expressed in degrees, divided by 4*Pi (i.e., A125560/(4*Pi)).

%D G. V. Brummelen, Heavenly Mathematics: The Forgotten Art of Spherical Trigonometry, Princeton University Press, 2012, ISBN 978-0691148922.

%H Stanislav Sykora, <a href="/A231981/b231981.txt">Table of n, a(n) for n = 4..2000</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Steradian">Steradian</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Square_degree">Square degree</a>

%H <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>

%F (180/Pi)^2.

%e 3282.80635001174379478169460799517550050122429938078818259773...

%t RealDigits[(180/Pi)^2,10,120][[1]] (* _Harvey P. Dale_, Nov 23 2019 *)

%Y Cf. A000796 (Pi), A125560 (full solid angle), A072097 (rad/deg), A019685 (deg/rad), A231982 (inverse, deg^2/sr), A231983 (square with 1 deg side, in sr), A231984 (square with 1 deg side, in square degrees), A231985, A231986 (square with 1 rad side, in sr), A231987.

%K nonn,cons,easy

%O 4,1

%A _Stanislav Sykora_, Nov 16 2013

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Last modified March 28 16:34 EDT 2024. Contains 371254 sequences. (Running on oeis4.)