A335563 Decimal expansion of the real part of the complex root of cos(x + i*y) = x - i*y with least x > 0 and y > 0.
9, 6, 2, 2, 6, 6, 0, 0, 6, 3, 3, 3, 0, 6, 0, 6, 8, 9, 4, 8, 5, 0, 8, 0, 9, 2, 5, 9, 3, 1, 0, 2, 5, 3, 7, 8, 2, 7, 5, 4, 7, 1, 4, 1, 9, 2, 8, 6, 6, 6, 4, 7, 4, 1, 2, 5, 5, 2, 0, 9, 5, 1, 6, 3, 4, 8, 1, 4, 2, 7, 7, 0, 0, 3, 8, 2, 6, 8, 9, 7, 7, 0, 6, 4, 4, 3, 8
Offset: 0
Examples
0.96226600633306068948508092593102537827547141928666...
Links
- T. H. Miller, On the numerical values of the roots of the equation cos x = x, Proc. Edinburgh Math. Soc., Vol. 9 (1890), pp. 80-83.
- T. Hugh Miller, On the imaginary roots of cos x = x, Proc. Edinburgh Math. Soc., Vol. 21 (1902), pp. 160-162 (the last 3 pages of the pdf file).
- Eric Weisstein's World of Mathematics, Dottie Number.
- Wikipedia, Dottie number.
Programs
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Mathematica
z = {x, y} /. FindRoot[{x == Cos[x]*Cosh[y], y == Sin[x]*Sinh[y]}, {{x, 1}, {y, 1}}, WorkingPrecision -> 100]; RealDigits[z[[1]], 10, 90][[1]]