Bài 2:
a: \(=\dfrac{7}{9}\left(\dfrac{7}{6}-\dfrac{19}{20}-\dfrac{1}{15}\right)+\dfrac{22}{5}\cdot\dfrac{1}{24}\)
\(=\dfrac{7}{9}\cdot\dfrac{3}{20}+\dfrac{22}{120}=\dfrac{7}{60}+\dfrac{11}{60}=\dfrac{18}{60}=\dfrac{3}{10}\)
b: \(=\left(\dfrac{35-32}{60}\right)^2+\dfrac{4}{5}\cdot\dfrac{70-45}{80}\)
\(=\dfrac{1}{400}+\dfrac{4\cdot25}{400}=\dfrac{101}{400}\)
Tìm giới hạn các dãy số sau
a) \(lim\dfrac{2^n+6^n-4^{n-1}}{3^n+6^{n+1}}\)
b) \(lim\dfrac{1+3+5+...+\left(2n+1\right)}{3n^2+4}\)
c) \(lim\dfrac{1+2+3+...+n}{n^2-3}\)
d) \(lim\left[\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{n\left(n+1\right)}\right]\)
e) \(lim\left[\dfrac{1}{1.3}+\dfrac{1}{3.5}+...+\dfrac{1}{\left(2n-1\right)\left(2n+1\right)}\right]\)
Tính các giới hạn
a) \(lim\dfrac{1+\dfrac{1}{3}+\left(\dfrac{1}{3}\right)^2+...+\left(\dfrac{1}{3}\right)^n}{1+\dfrac{1}{2}+\left(\dfrac{1}{2}\right)^2+...+\left(\dfrac{1}{2}\right)^n}\)
\(lim\left(n^3+n\sqrt{n}-5\right)\)
Giúp mình với ạ
1
a,Lim\(\sqrt{1+2n-n^3}\)
b,Lim\(\sqrt{n^2+2n+3}-\sqrt[3]{n^2+n^3}\)
c,Lim\(\dfrac{\left(2\sqrt{n}+1\right)\left(\sqrt{n}+3\right)}{\left(n+1\right)\left(n+2\right)}\)
d,\(\dfrac{4^{n+1}-3\times2^n}{3^{n+2}+2^n}\)
e,\(\dfrac{7^{n+1}-5^{n+2}+3}{2\times6^{n+1}-3^n+3}\)
f,\(\dfrac{\sqrt{n^4+1}}{n}\) -\(\dfrac{\sqrt{4n^6+1}}{n}\)
tính giới hạn của các hàm số sau:
a, limx→0\(\dfrac{\sqrt{1+x}-\sqrt{1-x}}{\sqrt[3]{1+x}-\sqrt{1-x}}\)
b, limx→0(\(\dfrac{1}{x}-\dfrac{1}{x^2}\))
c, limx→+∞ \(\dfrac{x^4-x^3+11}{2x-7}\)
d, limx→5 ( \(\dfrac{7}{\left(x-1\right)^2}.\dfrac{2x+1}{2x-3}\) )
Cho \(S_n=\dfrac{1}{1.3}+\dfrac{1}{3.5}+\dfrac{1}{5.7}+...+\dfrac{1}{\left(2n-1\right)\left(2n+1\right)}\). Kết quả giới hạn của limSn bằng:
A. \(\dfrac{1}{3}\)
B. \(\dfrac{1}{5}\)
C. \(\dfrac{1}{2}\)
D. 0
Tìm giới hạn :
lim \(\left[1+\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{16}+...+\dfrac{1}{n^2}\right]\)
Tính tổng các dãy số sau
a) S= \(1+0,1+\left(0,1\right)^2+\left(0,1\right)^3+...\)
b) S= \(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}+...\)
c) S= \(2+0,3+\left(0,3\right)^2+\left(0,3\right)^3+...\)
Biết \(\lim\limits_{x\rightarrow1}\left[\dfrac{5}{\left(x-1\right)^2}\left(a+\dfrac{x+1}{\sqrt{x^2-x+1}}-\dfrac{3x+3}{\sqrt{x}}\right)\right]=\dfrac{b}{c}\) là phan số tối giản. Tính a+b+c
