Calculer 1+5+5^2 + ... + 5^n
Mathématiques
vector
Question
Calculer
1+5+5^2 + ... + 5^n
1+5+5^2 + ... + 5^n
1 Réponse
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1. Réponse Anonyme
1+5+5^2 + ... + 5^n
=1.(1-5(n+1))/(1-5)
=1/4(5^(n+1)-1)
=5^(n+1)/4-1/4