Question

等比数列求极限方法?

Answer 1

an = a1q^(n-1)

case 1:if |q|>1

lim(n->无穷)an 不存在

case2:if q=1

an =a1

lim(n->无穷)an =1

case3:if q=-1

lim(n->无穷)an 不存在

case 1:if |q|无穷)an=a1