求极限,x趋向于0,lim(x的平方/(sin(x/3)的平方))求极限,x趋向于0,lim(x^2/(sin(x/3)^2))
问题描述:
求极限,x趋向于0,lim(x的平方/(sin(x/3)的平方))
求极限,x趋向于0,lim(x^2/(sin(x/3)^2))
答
用三角不等式做:sinx
答
运用罗比达定理的 x^2 / (x/3)^2=9
答
利用等价无穷小 sin(x/3)^2 (x/3)^2
=lim(x^2/((x/3)^2))=9;