OFFSET
0,1
COMMENTS
There are two unique real solutions to this equation, up to a multiple of 2*Pi. One is x ~ 2*Pi*n - 2.18722 and the other is x ~ 2*Pi*n - 0.443144. This decimal expansion is for n = 0 in the second approximation. See A259258 for the other solution set.
EXAMPLE
-0.443143645780469743105815193852418815...
MATHEMATICA
RealDigits[ArcCos[y/.Solve[y*(y^3+y^2-1)==1/2]][[4]], 10, 120][[1]] (* Vaclav Kotesovec, Jul 07 2015 *)
PROG
(PARI) default(realprecision, 2000); s=abs(solve(x=-1, 0, tan(x)+cos(x)+sin(x))); for(n=1, 100, s*=10; print1(floor(s)%10, ", "))
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Derek Orr, Jun 22 2015
STATUS
approved