login
Decimal expansion of greatest x having 4*x^2+3x=4*cos(x).
3

%I #5 Mar 30 2012 18:57:54

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

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

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

%N Decimal expansion of greatest x having 4*x^2+3x=4*cos(x).

%C See A197737 for a guide to related sequences. The Mathematica program includes a graph.

%e least x: -1.128864420523986139477004663061889573...

%e greatest x: 0.60607778364862645366579775799056291...

%t a = 4; b = 3; c = 4;

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

%t Plot[{f[x], g[x]}, {x, -2, 1}]

%t r1 = x /. FindRoot[f[x] == g[x], {x, -1.2, -1.1}, WorkingPrecision -> 110]

%t RealDigits[r1] (* A198367 *)

%t r2 = x /. FindRoot[f[x] == g[x], {x, .60, .61}, WorkingPrecision -> 110]

%t RealDigits[r2] (* A198368 *)

%Y Cf. A197737.

%K nonn,cons

%O 0,1

%A _Clark Kimberling_, Oct 24 2011