Question

Спасите МЕНЯЯЯЯ)) геометрическая прогрессия!

Answer 1

$frac{25^n-5^{2n-1}}{5^{2n}}=frac{5^{2n}-frac{1}{5}*5^{2n}}{5^{2n}}=frac{5^{2n}(1-frac{1}{5})}{5^{2n}}=1-frac{1}{5}=frac{4}{5}$

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