lim(x→0).(arctanx/x)的1/x^2次方=?题在为定式极限中,目测要用洛必达法则
问题描述:
lim(x→0).(arctanx/x)的1/x^2次方=?题在为定式极限中,目测要用洛必达法则
答
x→0lim (arctanx/x)^(1/x^2)=lim e^ln (arctanx/x)^(1/x^2)=e^lim ln (arctanx/x)^(1/x^2)考虑lim ln (arctanx/x)^(1/x^2)=lim ln(arctanx/x) / x^2=lim ln(1+arctanx/x-1) / x^2根据等价无穷小:ln(1+x)~x=lim (ar...