简单计算一下即可,答案如图所示
f(x) =lim(n->+∞) (1+x)/[1+x^(2n)]
case 1: x<-1
f(x) =lim(n->+∞) (1+x)/[1+x^(2n)] =0
case 2: x=-1
f(-1) =0
case 3: -1
case 4: x=1
f(1) =1
case 5 : x>1
f(x) =lim(n->+∞) (1+x)/[1+x^(2n)] = 0
ie
f(x)
=0 ; x≤-1
=1+x ; -1
=0 ; x>1