![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2014.2016}\)
\(=2.\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{2014.2016}\right)\)
\(=2.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{2014}-\frac{1}{2016}\right)\)
\(=2.\left(\frac{1}{2}-\frac{1}{2016}\right)\)
\(=2.\frac{1007}{2016}\)
\(=\frac{1007}{1008}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2014.2016}\)
\(=2.\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{2014.2016}\right)\)
\(=2.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{2014}-\frac{1}{2016}\right)\)
\(=2.\left(\frac{1}{2}-\frac{1}{2016}\right)\)
\(=2.\frac{1007}{2016}\)
\(=\frac{1007}{1008}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2012.2014}+\frac{4}{2014.2016}\)
\(=2\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{2012.2014}+\frac{2}{2014.2016}\right)\)
\(=2\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{2012}-\frac{1}{2014}+\frac{1}{2014}-\frac{1}{2016}\right)\)
\(=2\left(\frac{1}{2}-\frac{1}{2016}\right)\)
\(=2.\frac{1007}{2016}\)
\(=\frac{1007}{1008}\)
Study well ! >_<
\(\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2012.2014}+\frac{4}{2014.2016}\)
= \(2.\left(\frac{2}{2.4}+\frac{2}{4.6}+...+\frac{2}{2012.2014}+\frac{2}{2014.2016}\right)\)
= \(2.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{2012}-\frac{1}{2014}+\frac{1}{2014}-\frac{1}{2016}\right)\)
= \(2.\left(\frac{1}{2}-\frac{1}{2016}\right)\)
= 2 . 1007/2016 = 1007/1008
![](https://rs.olm.vn/images/avt/0.png?1311)
A = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... + 2005 + 2006 - 2007 - 2008 + 2009 + 2010 ( có 2010 số )
A = ( 1 + 2 - 3 - 4 ) + ( 5 + 6 - 7 - 8 ) + .... + ( 2005 + 2006 - 2007 - 2008 ) + ( 2009 + 2010 )
A = ( - 4 ) + ( - 4 ) + ... + ( - 4 ) + 4019 ( có 503 số )
A = ( - 4 ) . 502 + 4019
A = - 2008 + 4019
A = 2011.
CHÚC LÀM BÀI VUI VẺ
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\left(2-4\right)+\left(6-8\right)+\left(10-12\right)+.....+\left(2008-2010\right)+2012\)
\(=-2+\left(-2\right)+\left(-2\right)+....+\left(-2\right)+2012\)
\(=-2010+2012=-2\)
b
\(1+2-3+3+5+6-7-8+9+10+.....+2013+2014-2015-2016\)\(=\left(1+2-3\right)+\left(4+5+6-7-8\right)+....\)(các số phía sau cũng ghép tương tự)
\(=0\)
Nếu thấy bài làm của mình đúng thì tick nha bạn,mình xin chân thành cảm ơn.
![](https://rs.olm.vn/images/avt/0.png?1311)
tự làm là hạnh phúc của mỗi công dân.