1$\frac{1}{38}$ x 1$\frac{1}{39}$ x 1$\frac{1}{40}$ x …….. x 1$\frac{1}{2013}$ 23/08/2021 Bởi Adalynn 1$\frac{1}{38}$ x 1$\frac{1}{39}$ x 1$\frac{1}{40}$ x …….. x 1$\frac{1}{2013}$
Đáp án: `=53` Giải thích các bước giải: `1 1/38 xx 1 1/39 xx 1 1/40 xx …… xx 1 1/2013` `=(38+1)/38 xx (39+1)/39 xx (40+1)/40 xx ……. xx (2013+1)/2013` `=39/38 xx 40/39 xx 41/ 40 xx ……… xx 2014/2013` `=(39 xx 40 xx 41 xx …… xx 2014)/(38 xx 39 xx 40 xx ……. 2013)` `=2014/38` `=53` Bình luận
$\begin{array}{l}1\dfrac{1}{{38}} \times 1\dfrac{1}{{39}} \times 1\dfrac{1}{{40}} \times … \times 1\dfrac{1}{{2013}}\\ = \dfrac{{39}}{{38}} \times \dfrac{{40}}{{39}} \times \dfrac{{41}}{{40}} \times … \times \dfrac{{2014}}{{2013}}\\ = \dfrac{{39 \times 40 \times 41 \times … \times 2014}}{{38 \times 39 \times 40 \times … \times 2013}}\\ = \dfrac{{2014}}{{38}} = \dfrac{{38 \times 53}}{{38}} = 53\end{array}$ Bình luận
Đáp án:
`=53`
Giải thích các bước giải:
`1 1/38 xx 1 1/39 xx 1 1/40 xx …… xx 1 1/2013`
`=(38+1)/38 xx (39+1)/39 xx (40+1)/40 xx ……. xx (2013+1)/2013`
`=39/38 xx 40/39 xx 41/ 40 xx ……… xx 2014/2013`
`=(39 xx 40 xx 41 xx …… xx 2014)/(38 xx 39 xx 40 xx ……. 2013)`
`=2014/38`
`=53`
$\begin{array}{l}
1\dfrac{1}{{38}} \times 1\dfrac{1}{{39}} \times 1\dfrac{1}{{40}} \times … \times 1\dfrac{1}{{2013}}\\
= \dfrac{{39}}{{38}} \times \dfrac{{40}}{{39}} \times \dfrac{{41}}{{40}} \times … \times \dfrac{{2014}}{{2013}}\\
= \dfrac{{39 \times 40 \times 41 \times … \times 2014}}{{38 \times 39 \times 40 \times … \times 2013}}\\
= \dfrac{{2014}}{{38}} = \dfrac{{38 \times 53}}{{38}} = 53
\end{array}$