lim {x→0} (sinx - x) / (x²sinx)方法1：罗必塔= lim {x→0} (cosx - 1) / (2xsinx + x²cosx) 上下求导= lim {x→0} ( - sinx) / (2sinx + 2xcosx +2xcosx - x²sinx) 继续上下求导= lim {x→0} ( - ...