login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Decimal expansion of least x > 0 having cos(x) = cos(3*Pi*x/2)^2.
2

%I #8 Apr 10 2021 22:28:07

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

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

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

%N Decimal expansion of least x > 0 having cos(x) = cos(3*Pi*x/2)^2.

%C The Mathematica program includes a graph. See A197476 for a guide for the least x > 0 satisfying cos(b*x) = cos(c*x)^2 for selected b and c.

%e x=0.5036818076256583111503248157104914556657070609...

%t b = 1; c = 3*Pi/2; f[x_] := Sin[x]

%t t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .5, .51}, WorkingPrecision -> 200]

%t RealDigits[t] (* A197573 *)

%t Plot[{f[b*x], f[c*x]^2}, {x, 0, Pi/4}]

%Y Cf. A197133.

%K nonn,cons

%O 0,1

%A _Clark Kimberling_, Oct 16 2011