求判断无穷级数收敛性(绝对或条件收敛)∑ (-1^n) * sin(2/n)

问题描述:

求判断无穷级数收敛性(绝对或条件收敛)∑ (-1^n) * sin(2/n)

sin(2/n)>sin(2/n+1),limsin(2/n)=0,
莱布尼兹定理,收敛
limsin(2/n)/(2/n)=1,∑2/n发散,
条件收敛