这样的题目指接板用罗比达法则即可,用不着等价无穷小代换
lim(x→0)[(sinx-x)/x³]
=lim(x→0)[(cosx -1)/(3x²)]
=lim(x→0)[(-sinx)/(6x)]
=-1/6我还没看到罗必塔法则，请用等价无穷小来做