lim(x→0) (1/sin^2 x-1/x^2 cos^2 x)=? "limx趋向于0.(sin方x)分之一,...
问题描述:
lim(x→0) (1/sin^2 x-1/x^2 cos^2 x)=? "limx趋向于0.(sin方x)分之一,...
lim(x→0)(1/sin^2 x-1/x^2 cos^2 x)=?
"limx趋向于0.(sin方x)分之一,减,(x方乘以cos方x)分之一"
请写明过程.
我只知道最后答案是 -2/3
答
=lim (x²·cos²x - sin²x)/(sin²x·x²·cos²x)=lim (x²·cos²x - sin²x)/(x²·x²·1)《等价无穷小代换》=lim (x²·cos²x - sin²x) / x^4=li...