cp's OEIS Frontend

A198671 Decimal expansion of the absolute minimum of cos(x)+cos(2x)+cos(3x)+cos(4x).

%I A198671 #12 Dec 05 2016 10:40:13
%S A198671 1,5,1,9,5,5,7,8,8,1,6,4,2,8,4,8,2,5,1,3,6,9,4,2,6,8,1,1,3,2,9,8,5,0,
%T A198671 7,3,4,5,5,8,7,7,8,4,3,8,3,3,6,1,2,2,9,4,5,2,2,9,8,8,5,5,0,0,2,8,5,0,
%U A198671 6,9,8,9,3,4,7,1,3,4,1,7,9,3,5,7,7,0,4,2,5,5,5,8,2,7,4,8,0,5,4
%N A198671 Decimal expansion of the absolute minimum of cos(x)+cos(2x)+cos(3x)+cos(4x).
%C A198671 See A196361 for a guide to related sequences.
%e A198671 x=1.002750019227300659428346483723194...
%e A198671 min=-1.519557881642848251369426811329...
%t A198671 n = 4; f[t_] := Cos[t]; s[t_] := Sum[f[k*t], {k, 1, n}];
%t A198671 x = N[Minimize[s[t], t], 110]; u = Part[x, 1]
%t A198671 v = 2 Pi - t /. Part[x, 2]
%t A198671 RealDigits[u]  (* A198671 *)
%t A198671 RealDigits[v] (* A198672 *)
%t A198671 Plot[s[t], {t, -3 Pi, 3 Pi}]
%t A198671 (* Second program: *)
%t A198671 Root[-125 + 600x + 1227x^2 + 512x^3, 1] // RealDigits[#, 10, 99]& // First (* _Jean-François Alcover_, Feb 19 2013 *)
%Y A198671 Cf. A196361.
%K A198671 nonn,cons
%O A198671 1,2
%A A198671 _Clark Kimberling_, Oct 28 2011