2 câu trả lời
`( 1 - 1/2 )( 1 - 1/3 )( 1 - 1/4 )... ( 1 - 1/100 )`
`= 1/2. 2/3. 3/4. ... 99/100`
`= { 1. 2. 3. ... . 99 }/{ 2. 3. 4. ... . 100 }`
`= 1/100`
Ta có:
(1 - $\dfrac{1}{2}$ )·( 1 - $\dfrac{1}{3}$ )·( 1 - $\dfrac{1}{4}$ )·....·( 1 - $\dfrac{1}{100}$ )
=$\dfrac{1}{2}$·$\dfrac{2}{3}$·$\dfrac{3}{4}$·...·$\dfrac{99}{100}$
=$\dfrac{1·2·3·...·99}{2·3·4·...·100}$
=$\dfrac{1}{100}$
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