lim(x→0) (arctanx - sinx)/x³,洛必达法则= lim(x→0) [1/(1 + x²) - cosx]/(3x²)= (1/3)lim(x→0) (1 - cosx - x²cosx)/(x² + x⁴),洛必达法则= (1/3)(1/2)lim(x→0) (sinx - 2xcos...