%I #5 Mar 30 2012 18:57:55
%S 8,1,9,2,7,2,4,1,3,4,2,4,5,4,2,6,7,5,9,0,6,7,1,7,8,5,8,0,7,4,1,7,8,3,
%T 9,9,9,2,3,4,9,8,6,1,8,6,9,3,1,8,3,0,7,4,5,7,8,6,9,2,5,5,9,8,0,5,3,7,
%U 9,7,8,1,6,9,2,8,1,4,3,1,8,6,2,4,6,8,5,4,9,2,9,8,0,6,6,8,4,0,9
%N Decimal expansion of the least x>0 that gives the absolute minimum of cos(x)+cos(2x)+cos(3x)+cos(4x)+cos(5x).
%C See A196361 for a guide to related sequences.
%e x=0.8192724134245426759067178580741783999...
%e min=-1.728768207393169918251228314555655767777...
%t n = 5; f[t_] := Cos[t]; s[t_] := Sum[f[k*t], {k, 1, n}];
%t x = N[Minimize[s[t], t], 110]; u = Part[x, 1]
%t v = 2 Pi - t /. Part[x, 2]
%t RealDigits[u] (* A198673 *)
%t RealDigits[v] (* A198674 *)
%t Plot[s[t], {t, -3 Pi, 3 Pi}, PlotRange -> {-2, 6}]
%Y Cf. A196361.
%K nonn,cons
%O 0,1
%A _Clark Kimberling_, Oct 28 2011