Lim (x->infinity)((x+2)!+(x+1)!)/((x+2)!-(x+1)!)
(x+2)!+(x+1)! = (x+1)!(x+2)
(x+2)!-(x+1)! = (x+1)!(x+1)
Откуда
lim x-> +oo (x+2)/(x+1) = 1+1/(x+1) = 1+0 = 1