.5ln|(s+1/(r-1)-2/(r-1+sqrt(3r^2-1)))/(s-1/(r-1)+2/(r-1+sqrt(3r^2-1)))|-.03549457494861201693889,where r=(cbrt(108+12sqrt69)+cbrt(108-12sqrt69))/6,s=sqrt(1+sqrt2)(2/(sqrt2+r+sqrt(3r^2-1))-1/(sqrt2+r))