lim(x->0)ln(cosx)^1/x^2怎么算

问题描述:

lim(x->0)ln(cosx)^1/x^2怎么算

式子化为
ln(cosx)/x^2=ln(cosx-1+1)/x^2=(cosx-1)/x^2=-x^2/2x^2=-1/2