Question

Tính các giới hạn sau :

a) \(\lim\limits_{x\rightarrow-3}\dfrac{x^2-1}{x+1}\)

b) \(\lim\limits_{x\rightarrow-2}\dfrac{4-x^2}{x+2}\)

c) \(\lim\limits_{x\rightarrow6}\dfrac{\sqrt{x+3}-3}{x-6}\)

d) \(\lim\limits_{x\rightarrow+\infty}\dfrac{2x-6}{4-x}\)

e) \(\lim\limits_{x\rightarrow+\infty}\dfrac{17}{x^2+1}\)

f) \(\lim\limits_{x\rightarrow+\infty}\dfrac{-2x^2+x-1}{3+x}\)

 

Answer 1

a) = = -4.

b) = = (2-x) = 4.

c) =
= = = .

d) = = -2.

e) = 0 vì (x² + 1) = x²( 1 + ) = +∞.

f) = = -∞, vì > 0 với ∀x>0.