∵x→0时,1-cosx~x²/2∴1-cos√x x/2lim [1- √(cosx) ] / [x(1- cos√x )]= lim [1- √(cosx)] / (x²/2)= lim [1-√(cosx)][1+√cosx] / (x²/2)[1+√cosx]= lim (1- cosx) / (x²/2)(1+√cosx)=...