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Decimal expansion of least x > 0 having cos(x) = cos(Pi*x/4)^2.
2

%I #9 Apr 10 2021 11:46:18

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

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

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

%N Decimal expansion of least x > 0 having cos(x) = cos(Pi*x/4)^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=1.2783983856744496808872957323068365766686442...

%t b = 1; c = Pi/4; f[x_] := Cos[x]

%t t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, 1.27, 1.29},

%t WorkingPrecision -> 110]

%t RealDigits[t] (* A197495 *)

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

%Y Cf. A197476.

%K nonn,cons

%O 1,2

%A _Clark Kimberling_, Oct 15 2011