1/2*3+1/3*4+1/4*5+….+1/9*10 giúp mình nhé^^^^^ mình cần gấp 10/08/2021 Bởi Natalia 1/2*3+1/3*4+1/4*5+….+1/9*10 giúp mình nhé^^^^^ mình cần gấp
$\frac{1}{2.3}$ + $\frac{1}{3.4}$ + $\frac{1}{4.5}$ + … + $\frac{1}{9.10}$ = $\frac{1}{2}$ – $\frac{1}{3}$ + $\frac{1}{3}$ – $\frac{1}{4}$ + $\frac{1}{4}$ – $\frac{1}{5}$ + … + $\frac{1}{9}$ – $\frac{1}{10}$ = $\frac{1}{2}$ – $\frac{1}{10}$ = $\frac{2}{5}$ Bình luận
$\frac{1}{2.3}$ + $\frac{1}{3.4}$ + $\frac{1}{4.5}$ + … + $\frac{1}{9.10}$
= $\frac{1}{2}$ – $\frac{1}{3}$ + $\frac{1}{3}$ – $\frac{1}{4}$ + $\frac{1}{4}$ – $\frac{1}{5}$ + … + $\frac{1}{9}$ – $\frac{1}{10}$
= $\frac{1}{2}$ – $\frac{1}{10}$ = $\frac{2}{5}$
1/2.3+1/3.4+1/4.5+…+1/9.10=1/2-1/3+1/3-1/4+1/4-1/5+…+1/9-1/10=1/2-1/10=10/20-2/20=8/20=2/5