Помогите с пределами функций

Question

1) lim(x→∞) (3x^2+4x+5)/(7x^2+8x-1)

2) lim(x→∞) (x-1)/(x+2)

3) lim(x→∞) (3x^2-7x+2)/(x^2-4)

Дмитрий Майданов · Accepted Answer

Юлия Фалеева · Answer

1) lim(x→∞) (3x^2+4x+5)/(7x^2+8x-1)= lim(x→∞) (3+4/x+5/x^2)/(7+8/x-1/x^2)=(3+0+0)/(7+0-0)=3/7 
2) lim(x→∞) (x-1)/(x+2)=lim(x→∞) (1-1/x)/(1+2/x)=(110)/(1+0)=0

3) lim(x→∞) (3x^2-7x+2)/(x^2-4)= lim(x→∞) (3-7/x+2/x^2)/(1-4/x^2)=(3+0+0)/(1-0)=3