chứng minh rằng dãy sau giới hạn = 0 ; a) 1/(n+1)(n+2) 13/11/2021 Bởi Camila chứng minh rằng dãy sau giới hạn = 0 ; a) 1/(n+1)(n+2)
$\lim\dfrac{1}{(n+1)(n+2)}$ $=\lim\dfrac{1}{n^2+3n+2}$ $=\lim\dfrac{ \dfrac{1}{n^2} }{1+\dfrac{3}{n}+ \dfrac{2}{n^2} }$ $=\dfrac{0}{1+0+0}$ $=0$ Bình luận
$\quad \lim\dfrac{1}{(n+1)(n+2)}$ $=\lim\dfrac{\dfrac{1}{n^2}}{\left(1+\dfrac1n\right)\left(1+\dfrac2n\right)}$ $=\dfrac{0}{(1+0)(1+0)}$ $= 0$ Bình luận
$\lim\dfrac{1}{(n+1)(n+2)}$
$=\lim\dfrac{1}{n^2+3n+2}$
$=\lim\dfrac{ \dfrac{1}{n^2} }{1+\dfrac{3}{n}+ \dfrac{2}{n^2} }$
$=\dfrac{0}{1+0+0}$
$=0$
$\quad \lim\dfrac{1}{(n+1)(n+2)}$
$=\lim\dfrac{\dfrac{1}{n^2}}{\left(1+\dfrac1n\right)\left(1+\dfrac2n\right)}$
$=\dfrac{0}{(1+0)(1+0)}$
$= 0$