giới hạn \(lim\dfrac{1-2+4-...+\left(-2\right)^{n-1}}{1-3+9-...+\left(-3\right)^{n-1}}=\dfrac{4\left[1-\left(-2\right)^n\right]}{3\left[1-\left(-3\right)^n\right]}\) bằng?
Tìm các giới hạn sau:
a)\(lim\left[n^2\left(\sqrt{n^2+2}-\sqrt{n^2+4}\right)\right]\)
b)lim( \(\dfrac{3}{n-2}-5n\))
c) lim(\(\dfrac{n-1}{\sqrt{3}-n}-\dfrac{4}{2^{-n}}\))
d) \(lim\left(\dfrac{n^2-4}{n-2}-\dfrac{3n^2+4}{n}\right)\)
e) \(lim\dfrac{\sqrt{n^2+1}-n\sqrt{5}}{\sqrt{n^2+1}+n\sqrt{5}}\)
1. lim\(\dfrac{\left(n+2\right)^{50}.\left(n-3\right)^{80}}{\left(2n-1\right)^{40}.\left(3n-2\right)^{45}}\)
2. lim\(\dfrac{4^n}{2.3^n+4^n}\)
3. lim\(\dfrac{3^n-2.5^n}{7+3.5^n}\)
4. lim\(\dfrac{4^n-5^n}{2^{2n}+3.5^{2n}}\)
5. lim\(\dfrac{\left(-3\right)^n+5^n}{2.\left(-4\right)^n+5^n}\)
Tìm các giới hạn sau:
\(a,lim\dfrac{3+4^n}{1+3.4^{n+1}}\)
\(b,lim\dfrac{\left(-2\right)^n+3^n}{\left(-2\right)^{n+1}+3^{n+1}}\)
a) lim \(\dfrac{x\sqrt{x^2+1}-2x+1}{^3\sqrt{2x^3-2}+1}\)
x-> -∞
b) lim \(\dfrac{\left(2x+1\right)^3\left(x+2\right)^4}{\left(3-2x\right)^7}\)
x-> -∞
c) lim \(\dfrac{\sqrt{4x^2+x}+^3\sqrt{8x^3+x-1}}{^4\sqrt{x^4+3}}\)
x-> +∞
lim\(\dfrac{\left(2-n\right)\left(3+2n^3\right)}{2n^2-1}\)
lim\(\dfrac{\left(\sqrt{4n^2+1}-2n\right)n}{\sqrt[3]{4-n^3}+n}\)
Tính \(lim\dfrac{1+\dfrac{1}{3}+\left(\dfrac{1}{3}\right)^2+...+\left(\dfrac{1}{3}\right)^n}{1+\dfrac{2}{5}+\left(\dfrac{2}{5}\right)^2+...+\left(\dfrac{2}{5}\right)^n}\)
Tính giới hạn của L =lim \(\dfrac{\left(2n-n^3\right)\left(3n^2+1\right)}{\left(2n-1\right)\left(n^4-7\right)}\)
Tính :6/ lim\(\dfrac{-n^2+2n+1}{\sqrt{3n^4+2}}\)
7/ lim \(\dfrac{\sqrt{n^3-2n+5}}{3+5n}\)
10/ lim\(\dfrac{1+3+5+...+\left(2n+1\right)}{3n^3+4}\)