等差等比数列公式

1个回答

等差数列通项:an=a1+(n-1)d
等差数列前n项和:Sn=na1+[n(n-1)/2]d
等比数列通项:an=a1q^(n-1)
等比数列前项和:Sn=a1(q^n-1)/(q-1)