Đáp án+Giải thích các bước giải:
Ta có:
`2021/1+2009/2+2008/3+...+1/2010 : 1/2+1/3+1/4+1/5+...+2/2011`
`Đặt A=2021/1+2009/2+2008/3+...+1/2010 `
`A=2021/1+2009/2+2008/3+...+1/2010 `
`=(2009/2+1)+(2008/3+1)+...+(1/2021+1)`
` =2011/2+2011/3+2011/4+...+2011/2011`
`=2011*(1/2+1/3+1/4+1/5+...+1/2011)`
`A : 1/2+1/3+1/4+1/5+...+2/2011`
` =2011*(1/2+1/3+1/4+1/5+...+1/2011) : 1/2+1/3+1/4+1/5+...+2/2011`
`=2011`
Chúc bạn học tốt
