2/2.4 + 2/4.6 + 2/6.8 + ... + 2/98.100
= 1/2 - 1/4 + 1/4 - 1/6 + 1/6 - 1/8 + ... + 1/98 - 1/100
= 1/2 + (-1/4 + 1/4) + (-1/6 + 1/6) + ... + (-1/98 + 1/98) - 1/100
= 1/2 - 1/100 = 49/100
Ko viết đàu bài nha!
\(\Rightarrow=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{98}-\frac{1}{100}\)
\(\Rightarrow=\frac{1}{2}-\frac{1}{100}\)
\(=\frac{49}{100}\)
2/2.4 + 2/4.6 + 2/6.8 + ..............+ 2/98.100
=2.(1- 1/4 + 1/4 - 1/6 + 1/6 - 1/8+ .........+1/98 - 1/100)
=2.(1-1/100)=2.99/100 = 99/50
o0o_Chàng trai M52_o0o voi kudo shinichi , vay so 2 dau roi
