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Decimal expansion of 3^i + 3^(-i), where i = sqrt(-1).
1

%I #13 Feb 05 2014 03:26:43

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

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

%U 4,7,0,3,4,4,4,7,7,2,0,0,3,8,9,3,2

%N Decimal expansion of 3^i + 3^(-i), where i = sqrt(-1).

%C Approximately equals 1/log(3) = 0.9102... or 23/(15^(1/2)+4^(2/3))^(1/2) = 0.909664848... .

%F Equals 2*cos(log(3)). [_Bruno Berselli_, Feb 05 2014]

%e 0.909664845653219510055130287190084968176380338549139663022520422852...

%t RealDigits[ Chop[ N[ 3^I + 3^(-I), 111], 10^-110], 10, 111]

%Y Cf. A237192.

%K nonn,cons,easy

%O 0,1

%A _Robert G. Wilson v_, Feb 04 2014