Tính nhanh vs 1/6+1/12+1/20+1/30+1/42+1/56 09/11/2021 Bởi Adeline Tính nhanh vs 1/6+1/12+1/20+1/30+1/42+1/56
Đáp án: Giải thích các bước giải: $\frac{1}{6}$ + $\frac{1}{12}$ + $\frac{1}{20}$ + $\frac{1}{30}$ + $\frac{1}{42}$ +$\frac{1}{56}$ = $\frac{1}{2.3}$ + $\frac{1}{3.4}$ + $\frac{1}{4.5}$ + $\frac{1}{5.6}$ + $\frac{1}{6.7}$ + $\frac{1}{7.8}$ = $\frac{1}{2}$ – $\frac{1}{3}$ + $\frac{1}{3}$ – $\frac{1}{4}$ + ….. + $\frac{1}{7}$ – $\frac{1}{8}$ = $\frac{1}{2}$ – $\frac{1}{8}$ = $\frac{3}{8}$ Bình luận
Đáp án: Giải thích các bước giải: $\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}$ $ $ $=\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}$ $ $ $=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}$ $ $ $=\dfrac{1}{2}-\dfrac{1}{8}=\dfrac{3}{8}$ Bình luận
Đáp án:
Giải thích các bước giải:
$\frac{1}{6}$ + $\frac{1}{12}$ + $\frac{1}{20}$ + $\frac{1}{30}$ + $\frac{1}{42}$ +$\frac{1}{56}$
= $\frac{1}{2.3}$ + $\frac{1}{3.4}$ + $\frac{1}{4.5}$ + $\frac{1}{5.6}$ + $\frac{1}{6.7}$ + $\frac{1}{7.8}$
= $\frac{1}{2}$ – $\frac{1}{3}$ + $\frac{1}{3}$ – $\frac{1}{4}$ + ….. + $\frac{1}{7}$ – $\frac{1}{8}$
= $\frac{1}{2}$ – $\frac{1}{8}$
= $\frac{3}{8}$
Đáp án:
Giải thích các bước giải:
$\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}$
$ $
$=\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}$
$ $
$=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}$
$ $
$=\dfrac{1}{2}-\dfrac{1}{8}=\dfrac{3}{8}$