13/06/04 22:43:32.76
a(n)=a(0)r^n
s(n)=Σ[k=0, n]a(k)
=a(0)(1+r+…+r^n)
=a(0)(1+r^(n+1))/(1-r)
|r|<1のとき
lim[n→∞]s(n)=a(0)/(1-r)
13/06/04 22:43:32.76
a(n)=a(0)r^n
s(n)=Σ[k=0, n]a(k)
=a(0)(1+r+…+r^n)
=a(0)(1+r^(n+1))/(1-r)
|r|<1のとき
lim[n→∞]s(n)=a(0)/(1-r)