(2) 0/0 型，用罗必塔法则得原极限 = lim 2 e^(x^2) ∫ <0, x> e^(t^2)dt / [xe^(2x^2)]= lim 2 ∫ <0, x> e^(t^2)dt / [xe^(x^2)] ( 0/0 )= lim 2 e^(x^2) / [e^(x^2)+2x^2e^(x^2)]= lim 2 / (1+2x^2) = 2
