若<img src="https://zk.995w.com/lqwvjeImg/d0/d08ec4efc9949c1de12ffcadee28efa8.png" style="font-size: 20px;" >和<img src="https://zk.995w.com/lqwvjeImg/86/861399e9fc10f0b294c325de5113ae78.png" style="font-size: 20px;" >都存在，则<img src="https://zk.995w.com/lqwvjeImg/af/af8d6d93e008874ba456bbecdc59563c.png" style="font-size: 20px;" ><img src="https://zk.995w.com/lqwvjeImg/af/af8d6d93e008874ba456bbecdc59563c.png" style="font-size: 20px;" >在<img src="https://zk.995w.com/lqwvjeImg/75/75323a47576b84e1aac9f5cc7d63a276.png" style="font-size: 20px;" >处（）。<br>·连续且可微<br>·连续但不一定可为微<br>·可微但不一定连续<br>·不一定连续，且不一定可微