Để giới hạn đã cho hữu hạn \(\Rightarrow a=-2\)
\(\lim\limits_{x\rightarrow+\infty}\left(\sqrt{4x^2+8x-1}-\left(2x+b\right)\right)=\lim\limits_{x\rightarrow}\dfrac{4x^2+8x-1-\left(4x^2+4bx+b^2\right)}{\sqrt{4x^2+8x-1}+2x+b}\)
\(=\lim\limits_{x\rightarrow}\dfrac{\left(8-4b\right)x-1-b^2}{\sqrt{4x^2+8x-1}+2x+b}=\dfrac{8-4b}{4}=2-b=3\)
\(\Rightarrow b=-1\)
tính giới hạn
a) \(\lim\limits_{x\rightarrow+\infty}\left(2x-\sqrt{x^2+4x-3}\right)\)
b) \(\lim\limits_{x\rightarrow+\infty}\left(\sqrt{4x^2-3x+1}-2x\right)\)
a) \(\lim\limits_{x\rightarrow+\infty}\)\(^{3_{\sqrt{x^3+4x^2}-x}}\)
b) \(f\left(x\right)=\left\{{}\begin{matrix}\dfrac{4x-1}{x-1}neux>1\\7x+1neux< 1\end{matrix}\right.\)
Tính \(\lim\limits f\left(x\right)_{x\rightarrow1^+}\) , \(\lim\limits f\left(x\right)_{x\rightarrow1^-}\)
1) Tính giới hạn \(\lim\limits_{n\rightarrow\infty}\dfrac{-n^2+2n+1}{\sqrt{3n^4+2}}\)
2) Tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\dfrac{4n-\sqrt{16n^2+1}}{n+1}\right)\)
3) Tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\dfrac{\sqrt{9n^2+n+1}-3n}{2n}\right)\)
Tìm các giới hạn sau:
\(\lim\limits_{x\rightarrow-\infty}\) \(\dfrac{\sqrt{x^6+2}}{3\text{x}^3-1}\)
\(\lim\limits_{x\rightarrow+\infty}\) \(\dfrac{\sqrt{x^6+2}}{3\text{x}^3-1}\)
\(\lim\limits_{x\rightarrow-\infty}\) \(\left(\sqrt{2\text{x}^2+1}+x\right)\)
\(\lim\limits_{x\rightarrow1}\) \(\dfrac{2\text{x}^3-5\text{x}-4}{\left(x+1\right)^2}\)
1) Tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\sqrt[3]{n^3+3n^2+1}-n\right)\)
2) Tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\sqrt{4n^2+1}-\sqrt[3]{8n^3+n}\right)\)
Tính các giới hạn sau :
1/\(\lim\limits_{x\rightarrow-\infty}\left(\sqrt{4x^2-3x+1}+2x\right)\)
2/\(lim\left(\sqrt{4n^2+2n+1}-2n+2020\right)\)
1) tính \(\lim\limits_{n\rightarrow\infty}\dfrac{6n-8}{n-1}\)
2) \(\lim\limits_{n\rightarrow\infty}\dfrac{n^2+5n-3}{4n^3-2n+5}\)
3) \(\lim\limits_{n\rightarrow\infty}\left(-2n^5+4x^4-3n^2+4\right)\)
11) \(\lim\limits_{x->1}\) \(\dfrac{3_{\sqrt{4x-1}-\sqrt{4x-3}}}{x-1}\)
11) \(\lim\limits_{x->4}\dfrac{4x-1}{x^2-8x+16}\)
12) \(\lim\limits_{x->2}\)\(\dfrac{4-x^2}{x^3-8}\)
13) \(\lim\limits_{x->+\infty}\left(3_{\sqrt{x^3+4x^2}-x}\right)\)
1) tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\sqrt{n^2+6n}-n\right)\)
2) tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\sqrt{n+1}-\sqrt{n-1}\right)\)
1) Tính \(I=\lim\limits_{n\rightarrow\infty}\left(\sqrt{n^2+2}-\sqrt{n^2-1}\right)\)
2) Tính giới hạn \(\lim\limits_{n\rightarrow\infty}\left(\sqrt{n^2+2n+2}+n\right)\)
