

A197521


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


3



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

1,1


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.
Conjecture: the constant here, 3.52133782..., is 3 plus the constant in A197383, the latter being the least t>0 satisfying sin(pi*t/6)=(sin pi*t/3)^2.


LINKS

Table of n, a(n) for n=1..99.


EXAMPLE

x=3.521337829571715698691988564454917977309181394...


MATHEMATICA

b = Pi/2; c = Pi/3; f[x_] := Cos[x]
t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, 3.5, 3.53}, WorkingPrecision > 200]
RealDigits[t] (* A197521, appears to be 3+A197383 *)
Plot[{f[b*x], f[c*x]^2}, {x, 0, 4}]
RealDigits[ 6*ArcCos[ Root[ 1  4# + 4#^3 & , 2]]/Pi, 10, 99] // First (* JeanFrançois Alcover, Feb 19 2013 *)


CROSSREFS

Cf. A197476.
Sequence in context: A021288 A140735 A183206 * A161865 A145325 A282194
Adjacent sequences: A197518 A197519 A197520 * A197522 A197523 A197524


KEYWORD

nonn,cons


AUTHOR

Clark Kimberling, Oct 16 2011


STATUS

approved



