IoT: networks of physical devices embedded with sensors, software, and connectivity that enable data collection and exchange....

极限 注意要求的极限值的正负性，区分： lim⁡x→∞f(x)\displaystyle \lim_{x \to \infty} f(x)x→∞lim​f(x) lim⁡x→−∞f(x)\displaystyle \lim_{x \to -\in...