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Decimal expansion of least x satisfying 8*x^2 - 1 = sec(x) and 0 < x < Pi.
3

%I #12 Jan 30 2025 15:42:59

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

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

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

%N Decimal expansion of least x satisfying 8*x^2 - 1 = sec(x) and 0 < x < Pi.

%C See A201397 for a guide to related sequences. The Mathematica program includes a graph.

%H <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.

%e least: 0.518577002201711458253109820417244...

%e greatest: 1.5130057374477490977746930540120...

%t a = 8; c = -1;

%t f[x_] := a*x^2 + c; g[x_] := Sec[x]

%t Plot[{f[x], g[x]}, {x, 0, Pi/2}, {AxesOrigin -> {0, 0}}]

%t r = x /. FindRoot[f[x] == g[x], {x, .5, .6}, WorkingPrecision -> 110]

%t RealDigits[r] (* A201525 *)

%t r = x /. FindRoot[f[x] == g[x], {x, 1.5, 1.6}, WorkingPrecision -> 110]

%t RealDigits[r] (* A201526 *)

%Y Cf. A201397.

%K nonn,cons

%O 0,1

%A _Clark Kimberling_, Dec 02 2011