Toán 1/2 – 1/2 . 3 – 1/3 . 4 – 1/4 . 5 – …….-1020/1021 02/09/2021 By Adeline 1/2 – 1/2 . 3 – 1/3 . 4 – 1/4 . 5 – …….-1020/1021
Đáp án: Giải thích các bước giải: $\text{Ta có:$\frac{1}{2}-\frac{1}{2.3}-\frac{1}{3.4}-\frac{1}{4.5}-…-\frac{1}{1020.1021}$}$ $\text{$=\frac{1}{2}-(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+…+\frac{1}{1020.1021})$}$ $\text{$=\frac{1}{2}-(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+…+\frac{1}{1020}-\frac{1}{1021})$}$ $\text{$=\frac{1}{2}-(\frac{1}{2}-\frac{1}{1021})=\frac{1}{1021}$}$ Trả lời
Đáp án: `1/2 – 1/{2 . 3} – 1/{3 . 4} – 1/{4 . 5} – …….-1/{1020.1021}` `=1/2 -(1/{2 . 3} + 1/{3 . 4} + 1/{4 . 5} + …….+1/{1020.1021})` `=1/2 -(1/2-1/3+1/3-…+1/1020-1/1021)` `=1/2-(1/2-1/1021)` `=1/2-1023/2042` `=-1/1021` Trả lời
Đáp án:
Giải thích các bước giải:
$\text{Ta có:$\frac{1}{2}-\frac{1}{2.3}-\frac{1}{3.4}-\frac{1}{4.5}-…-\frac{1}{1020.1021}$}$ $\text{$=\frac{1}{2}-(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+…+\frac{1}{1020.1021})$}$
$\text{$=\frac{1}{2}-(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+…+\frac{1}{1020}-\frac{1}{1021})$}$
$\text{$=\frac{1}{2}-(\frac{1}{2}-\frac{1}{1021})=\frac{1}{1021}$}$
Đáp án:
`1/2 – 1/{2 . 3} – 1/{3 . 4} – 1/{4 . 5} – …….-1/{1020.1021}`
`=1/2 -(1/{2 . 3} + 1/{3 . 4} + 1/{4 . 5} + …….+1/{1020.1021})`
`=1/2 -(1/2-1/3+1/3-…+1/1020-1/1021)`
`=1/2-(1/2-1/1021)`
`=1/2-1023/2042`
`=-1/1021`