cp's OEIS Frontend

A198672 Decimal expansion of the least x>0 that gives the absolute minimum of cos(x)+cos(2x)+cos(3x)+cos(4x).

%I A198672 #5 Mar 30 2012 18:57:55
%S A198672 1,0,0,2,7,5,0,0,1,9,2,2,7,3,0,0,6,5,9,4,2,8,3,4,6,4,8,3,7,2,3,1,9,4,
%T A198672 3,2,3,8,6,2,7,2,3,3,3,1,8,4,0,9,7,2,9,6,4,8,6,4,9,3,1,0,1,9,1,0,5,3,
%U A198672 4,9,1,3,5,9,2,5,7,5,1,9,9,8,6,1,3,3,4,6,1,9,7,7,6,3,6,5,5,3,7
%N A198672 Decimal expansion of the least x>0 that gives the absolute minimum of cos(x)+cos(2x)+cos(3x)+cos(4x).
%C A198672 See A196361 for a guide to related sequences.
%e A198672 x=1.002750019227300659428346483723194323862...
%e A198672 min(f(x))=-1.519557881642848251369426811329...
%t A198672 n = 4; f[t_] := Cos[t]; s[t_] := Sum[f[k*t], {k, 1, n}];
%t A198672 x = N[Minimize[s[t], t], 110]; u = Part[x, 1]
%t A198672 v = 2 Pi - t /. Part[x, 2]
%t A198672 RealDigits[u] (* A198671 *)
%t A198672 RealDigits[v] (* A198672 *)
%t A198672 Plot[s[t], {t, -3 Pi, 3 Pi}]
%Y A198672 Cf. A196361, A198671.
%K A198672 nonn,cons
%O A198672 1,4
%A A198672 _Clark Kimberling_, Oct 28 2011