OFFSET
1,1
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 = 1 in the first approximation. See A259259 for the other solution set.
EXAMPLE
4.0905606739537756911944516590724078...
MATHEMATICA
RealDigits[2*Pi - ArcCos[y/.Solve[y*(y^3+y^2-1)==1/2]][[3]], 10, 120][[1]] (* Vaclav Kotesovec, Jul 07 2015 *)
RealDigits[x/.FindRoot[Sin[x]+Cos[x]+Tan[x]==0, {x, 4}, WorkingPrecision-> 120]][[1]] (* Harvey P. Dale, Sep 23 2020 *)
PROG
(PARI) default(realprecision, 2000); s=solve(x=3, 4.3, tan(x)+cos(x)+sin(x)); for(n=1, 100, print1(floor(s)%10, ", "); s=10*s)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Derek Orr, Jun 22 2015
STATUS
approved