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1/3*5+ 1/5*7+ 1/7*9+...+1/2019*2021​

Răspuns :

Răspuns:

Explicație pas cu pas:

1/3*5 = 1/3 - 1/5

1/5*7 = 1/5 - 1/7

1/7*9 = 1/7 - 1/9

..........

1/2019*2021 = 1/2019 - 1/2021

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1/3*5 + 1/5*7 + 1/7*9 + .....+ 1/2019*2021

= 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 +....+ 1/2019 - 1/2021

= 1/3 - 1/2021 = 2021/6063 - 3/6063 = 2018/6063

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