limx/根号1-cosx=?x趋于正0

题目

limx/根号1-cosx=?x趋于正0

答案

limx/根号(1-cosx)
=limx/根号[2(sinx/2)^2]
=limx/根号[2*x^2/4]
=1/根号[1/2]
=根号2