A201531 - OEIS

%I #10 Jan 30 2025 15:44:00

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

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

%U 1,7,8,6,3,0,7,4,4,3,1,6,8,3,5,3,2,4,0,7,4,8,1,0,3,5,6,5,8,0,4

%N Decimal expansion of x satisfying 2*x^2 + 3 = 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 1.42918273259701836782028842157379367447...

%t a = 2; c = 3;

%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, 1.4, 1.5}, WorkingPrecision -> 110]

%t RealDigits[r]   (* A201531 *)

%Y Cf. A201397.

%K nonn,cons

%O 1,2

%A _Clark Kimberling_, Dec 02 2011