A197495 Decimal expansion of least x > 0 having cos(x) = cos(Pi*x/4)^2.

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, 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, 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

Offset: 1

Author

Clark Kimberling, Oct 15 2011

Keywords

• nonn
• cons

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

Examples

			1.2783983856744496808872957323068365766686442...
		

Crossrefs

Cf. A197476.

Programs

Mathematica

b = 1; c = Pi/4; f[x_] := Cos[x]
t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, 1.27, 1.29},
   WorkingPrecision -> 110]
RealDigits[t] (* A197495 *)
Plot[{f[b*x], f[c*x]^2}, {x, 0, Pi/2}]