Tính A=1 - \[ \frac{2}{3.5} - \frac{2}{5.7} - \frac{2}{7.9} - \ldots - \frac{2}{63.65}

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4) A=1 -
\[
\frac{2}{3.5} - \frac{2}{5.7} - \frac{2}{7.9} - \ldots - \frac{2}{63.65}
\]

5) 1 - \(\frac{1}{9} - \frac{1}{9} - \frac{1}{9}\)