S_5 = a \cdot racr^5 - 1r - 1 = 1 \cdot rac3^5 - 13 - 1 = rac243 - 12 = rac2422 = 121. - AMAZONAWS

📅 March 11, 2026 👤 scraface

Mar 11, 2026

$S_5 = a \cdot rac{r^5 - 1}{r - 1} = 1 \cdot rac{3^5 - 1}{3 - 1} = rac{243 - 1}{2} = rac{242}{2} = 121.$