polyroot behaviour

Colleagues,

g <- function(x) ( x^11 + 1000*x^10 + 500 *x^9 + 1 )
coeffs <- c(1, rep(0, 8), 500, 1000, 1)
roots <- polyroot(coeffs)

Output

[1]    0.25770068+3.958197e-01i
 [2]   -0.34615184+3.782848e-01i
 [3]   -0.04089779-4.838134e-01i
 [4]    0.44124314-1.517731e-01i
 [5]   -0.04089779+4.838134e-01i
 [6]   -0.56201931-1.282822e-01i
 [7]   -0.34615184-3.782848e-01i
 [8]    0.44124314+1.517731e-01i
 [9]   -0.56201931+1.282822e-01i
[10]    0.25770068-3.958197e-01i
[11] -999.49974975+1.110223e-16i

[11] -999.49974975+1.110223e-16i  makes  no sense since f>0 for all x

Why does polyroot do this?

Thomas Subia