求x->0lim(arctanx-x)/[xln(1+2x^2)]的极限
问题描述:
求x->0lim(arctanx-x)/[xln(1+2x^2)]的极限
答
lim(x->0)(arctanx-x)/[xln(1+2x^2)]
=lim(x->0)(arctanx-x)/x^3
=lim(x->0)[1/(1+x^2)-1]/(3x^2)
=lim(x->0)-x^2/[(1+x^2)(3x^2)]
=lim(x->0)-x^2/[(3x^2)]
=-1/3