0
lim x arctan1/x
=lim (arctan1/x)/(1/x)
=lim (1/(1+1/x^2)*(-1/x^2))/(-1/x^2) (罗比达法则)
=lim (1/(1+1/x^2))
=lim (x^2/(1+x^2))
=0
多谢回答该问题的另一位高手!