A197488 Decimal expansion of least x > 0 having cos(6x) = (cos 4x)^2.

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

Offset: 0

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.

Also the solution of the least x > 0 satisfying (cos(x))^2 + (sin(3x))^2 = 1/2. See A197739. - Clark Kimberling, Oct 19 2011

Examples

			0.9218840880158607848199692488618106365729956...
		

Links

• Index entries for transcendental numbers.

Crossrefs

Cf. A197476.

Programs

Mathematica

b = 6; c = 4; f[x_] := Cos[x]
t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .92, .93}, WorkingPrecision -> 100]
RealDigits[t] (* A197488 *)
Plot[{f[b*x], f[c*x]^2}, {x, 0, 1}]
RealDigits[ ArcCos[ Root[ -2 + 8#^2 - 6#^4 + #^6 & , 5]/2], 10, 99] // First (* Jean-François Alcover, Feb 19 2013 *)

Extensions

Digits from a(92) on corrected by Jean-François Alcover, Feb 19 2013