设<img src=https://huaweicloudobs.ahjxjy.cn/C67CBDA727FEA56C7AB111CAB6F951AD.png title=QQ图片20160224215718.png alt=QQ图片20160224215718.png width=212 height=25 border=0 vspace=0 style=width: 212px; height: 25px;/>,则( )
①
<img src=https://huaweicloudobs.ahjxjy.cn/DF3DA077C2189146990B3800DA1E18ED.png title=QQ图片20160224214023.png alt=QQ图片20160224214023.png/>为极值点
②
<img src=https://huaweicloudobs.ahjxjy.cn/DF3DA077C2189146990B3800DA1E18ED.png title=QQ图片20160224214023.png alt=QQ图片20160224214023.png/>为驻点
③
<img src=https://huaweicloudobs.ahjxjy.cn/DF3DA077C2189146990B3800DA1E18ED.png title=QQ图片20160224214023.png alt=QQ图片20160224214023.png/>为连续点
④
<img src=https://huaweicloudobs.ahjxjy.cn/EA6FB79FF8DF7A9F3A2D0CEB093C717F.png title=QQ图片20160224214006.png alt=QQ图片20160224214006.png/>在<img src=https://huaweicloudobs.ahjxjy.cn/DF3DA077C2189146990B3800DA1E18ED.png title=QQ图片20160224214023.png alt=QQ图片20160224214023.png/>有定义