Question

求极限……题目如图

Answer 1

n²sin²(θ/n)=θ²[sin(θ/n)/(θ/n)]²
n->∞lim[sin(θ/n)/(θ/n)]=1

∴该题的极限为 -θ²/2

Answer 2

sin^2(s/n)等价于(s/n)^2,所以n^2*sin^2(s/n)等价于s^2