\(=2.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2017.2018}\right)\)
\(=2.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{2017}-\frac{1}{2018}\right)\)
\(=2.\left(1-\frac{1}{2018}\right)\)
\(=2.\frac{2017}{2018}\)
\(=\frac{2017}{1009}\)
quy tử số thành 1
A = 2.(1/1.2+1/3.2+1/3.4+... + 1/2017.2018)
A= 2. (1- 1/2018)
Tính nốt nha
A=\(\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+......+\frac{2}{2017.2018}\)
A=\(2-\frac{2}{2}+\frac{2}{2}-\frac{2}{3}-...\frac{2}{2017}-\frac{2}{2018}\)
A=\(2-\frac{2}{2018}\)
A=\(\frac{1017}{509}\)
A+2/1.2+2/2.3+2/3.4+...+2/2017.2018
=2/1-2/2+2/2-2/3+2/3-2/4+2/4...2/2017-2/2018
=2/1-2/2018
=...
theo mk nghĩ là như thế.Nếu sai thì thông cảm cho mk nhé, nếu đúng thì k cho mk cái nha bn.Chúc bn hc tốt
