%I #16 Oct 27 2023 10:32:51
%S 7,7,0,9,1,6,9,9,7,0,5,9,2,4,8,1,0,0,8,2,5,1,4,6,3,6,9,3,0,7,0,2,6,9,
%T 6,7,2,5,5,0,5,3,1,1,9,3,6,3,3,2,8,6,1,5,1,0,0,5,9,8,4,9,2,9,7,6,7,3,
%U 5,1,0,3,2,8,2,0
%N Decimal expansion of the real root of x^3 + 2*x - 2.
%C The other two roots are (w1*(27 + 3*sqrt(105))^(1/3) + (27 - 3*sqrt(105))^(1/3))/3 = -0.3854584985... + 1.5638845105...*i, and its complex conjugate, where w1 = (-1 + sqrt(3)*i)/2 = exp(2*Pi*i/3) is one of the complex roots of x^3 - 1.
%C Using hyperbolic functions these roots are -(1/3)*sqrt(6)*(sinh((1/3)* arcsinh((3/4)*sqrt(6))) + sqrt(3)*cosh((1/3)*arcsinh((3/4)*sqrt(6)))*i), and its complex conjugate.
%H <a href="/index/Al#algebraic_03">Index entries for algebraic numbers, degree 3</a>
%F r = (1/3)*(27 + 3*sqrt(105))^(1/3) - 2/(27 + 3*sqrt(105))^(1/3).
%F r = ((27 + 3*sqrt(105))^(1/3)+ w1*(27 - 3*sqrt(105))^(1/3))/3, where w1 = (-1 + sqrt(3)*i)/2 = exp(2*Pi*i/3) is one of the complex roots of x^3 - 1.
%F r = (2/3)*sqrt(6)*sinh((1/3)*arcsinh((3/4)*sqrt(6))).
%e 0.770916997059248100825146369307026967255053119363328615100598492976735103...
%t RealDigits[x /. FindRoot[x^3 + 2*x - 2, {x, 1}, WorkingPrecision -> 120]][[1]] (* _Amiram Eldar_, Sep 21 2022 *)
%o (PARI) solve(x=0, 1, x^3 + 2*x - 2) \\ _Michel Marcus_, Sep 23 2022
%o (PARI) polrootsreal(x^3 + 2*x - 2)[1] \\ _Charles R Greathouse IV_, Sep 30 2022
%Y Cf. A273066.
%K nonn,cons,easy
%O 0,1
%A _Wolfdieter Lang_, Sep 20 2022