• 2021-06-20
    若偏导数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/a1b21fe4866c4a31bc3d618a2ea3c815.png存在,则http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/7cb9e1dd6acf40e6abfc4d2b731eeef2.png在点http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/e1a9c8e68bfc4a8f949807cf6c5f0a12.png处连续。

    举一反三