若http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/58b41e7063be4bf5a0cae88cf3f74248.png在点http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/2ae9760be5dd4e36afe78475f06dfeed.png处可微，则偏导数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/13ff091b7e4d457cbbe0302be816ba67.png一定存在。
举一反三
- 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。<span style="font-family: 宋体;</span><br><br>
- 若http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/2276b14202c34911935ade73ce2adbac.png在点http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/6bf4c35030e343beb3815627b042a0e6.png处连续，则偏导数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/987d855cc07242c3b7e7a3c70482da4e.png一定存在。<span style="font-family: 宋体;</span><br><span style=";font-family:宋体;font-size:16px<span style="font-family:宋体</span></span><br>
- 若级数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/40dd933d966d4d23be58c68c8e811716.png发散，则http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/faaa6bd9061c4c139fa21f21083e747b.pnghttp://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/f87d20317ab74d1f85d08286f1778fed.png收敛。 ( )<span style="font-family: 宋体;</span><br><span style=";font-family:宋体;font-size:16px<span style="font-family:宋体</span></span><br>
- 若http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/5c06779096154f7c8b702d66edce8df1.png在点http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/7d26b1d151c9438485fa20b9ca38af20.png处可微，则偏导数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/518027493bf540a1a080f49503d0afb3.png一定连续。<br>
- 若级数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/7b1a57e50e28470a94cfc69798ff4e92.png发散，则级数http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/8dfdfcf264264745ae2e15830d060573.png（http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/150299b5282a4ae9a7a91a19839d4460.png为常数） 也发散。( )<span style="font-family: 宋体;</span><br><br>