lim(x→0) [∫(0到x) (e^t)sin(t^2) dt]/x^3=lim(x→0) (e^x)sin(x^2)/(3x^2),洛必达法则=(1/3)lim(x→0) sin(x^2)/(x^2)*lim(x→0) e^x=(1/3)*1*1=1/3
