Question

Gía trị biểu thức:

\(\frac{1}{1.3}+\frac{1}{2.4}+\frac{1}{3.5}+\frac{1}{4.6}+\frac{1}{5.7}+\frac{1}{6.8}+\frac{1}{7.9}+\frac{1}{8.10}\)

Answer 1

=\(\frac{1}{2}.\left(\frac{2}{1.3}+\frac{2}{2.4}+...+\frac{2}{8.10}\right)\)

= \(\frac{1}{2}.\left(1-\frac{1}{3}+\frac{1}{2}-\frac{1}{4}+....+\frac{1}{8}-\frac{1}{10}\right)\)

= \(\frac{1}{2}.\left(1+\frac{1}{2}-\frac{1}{9}-\frac{1}{10}\right)\)

=\(\frac{29}{45}\)

Answer 2

29/45 bạn nhé

Answer 3

<br class="Apple-interchange-newline"><div id="inner-editor"></div>S=11.3 −12.4 +13.5 −14.6 +15.7 −16.8 +17.9 −18.10 

(11.3 +13.5 +15.7 +17.9 )−12.4 −14.6 −16.8 −18.10 

=12 (21.3 +23.5 +25.7 +27.9 )−(12.4 +14.6 +16.8 +18.10 )

=12 (21.3 +23.5 +25.7 +27.9 )−12 (22.4 +24.6 +26.8 +28.10 )

=12 (1−13 +13 −15 +15 −17 +17 −19 )−12 (12 −14 +14 −16 +16 −18 +18 −110 )

=12 (1−19 )−12 (12 −110 )

=12 (1−19 −12 +110 )

Answer 4

29/45 nha !

Answer 5

ket qua la 29/45

Answer 6

Kết quả: 29/54

Answer 7

\(\frac{1}{1.3}+\frac{1}{2.4}+\frac{1}{3.5}+\frac{1}{4.6}+\frac{1}{5.7}+\frac{1}{6.8}+\frac{1}{7.9}+\frac{1}{8.10}\)

\(=\left(1-\frac{1}{3}\right)+\left(\frac{1}{2}-\frac{1}{4}\right)+\left(\frac{1}{3}-\frac{1}{5}\right)+\left(\frac{1}{4}-\frac{1}{6}\right)+\left(\frac{1}{6}-\frac{1}{8}\right)\)\(+\left(\frac{1}{7}-\frac{1}{9}\right)+\left(\frac{1}{8}-\frac{1}{10}\right)\)

\(=1-\frac{1}{2}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}-\frac{1}{8}-\frac{1}{10}\)

\(=\frac{-451}{2520}\)

Answer 8

1/1.3 + 1/2.4 + 1/3.5 + 1/4.6 + 1/5.7 + 1/6.8 + 1/7.9 + 1/8.10

=1/2 . (1- 1/3 + 1/2 - 1/4 + 1/3 - 1/5 + 1/4 - 1/6 + 1/5 - 1/7 +1/6 -1/8 +1/7 -1/9 +1/8 -1/10 )

=1/2 . 58/45

=29/45

Answer 9

29/45

Answer 10

29/45 vậy đòi làm khó mình

Answer 11

24/7 giờ bn nhé!

Answer 12

Đáp án : 29/ 45.

Answer 13

29/45 nha bạn 

nhớ k cho mk nha

Answer 14

=(\(\)\(1-\frac{1}{3}\)\(+\frac{1}{2}\)\(-\frac{1}{4}\)\(+...+\frac{1}{8}\)\(-\frac{1}{10}\)):2

=(\(1+\frac{1}{2}\)\(-\frac{1}{10}\)):2

=\(\frac{7}{10}\)

Hok tot. mk nghĩ thế thôi chắc sai mà mk l, tắt ó!!!