limx(sin1/x^2)^1/2 x→－∞ =lim[-(-x)](sin1/x^2)^1/2=-lim[(-x^2)sin(1/x^2)]^1/2=-lim[x^2sin(1/x^2)]^1/2=-lim{sin(1/x^2)/[1/x^2]}^1/2当x→－∞时 1/x^2→0令t=1/x^2,代入原式=-lim(sint/t)^1/2又t→0 lim(si...