A197490 Decimal expansion of least x > 0 having cos(x) = cos(2*Pi*x)^2.

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

Offset

0,1

Comments

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.

This number is irrational. I cannot prove it to be algebraic or transcendental. - Charles R Greathouse IV, Feb 16 2025

Links

Table of n, a(n) for n=0..98.

Example

0.564425476062659099384003228937788297677...

Mathematica

b = 1; c = 2 Pi; f[x_] := Cos[x]
t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .56, .57}, WorkingPrecision -> 110]
RealDigits[t] (* A197490 *)
Plot[{f[b*x], f[c*x]^2}, {x, 0, Pi/4}]

Crossrefs

Cf. A197476.

Sequence in context: A019818 A187146 A128632 * A319015 A229481 A304490

Adjacent sequences: A197487 A197488 A197489 * A197491 A197492 A197493

Keyword

nonn,cons

Author

Clark Kimberling, Oct 15 2011

Status

approved