二元函数<img src=https://huaweicloudobs.ahjxjy.cn/970CBEFB46F8FE0F0043C9AC8113E3B1.png title=7Q[G4PYYU6I{UAZ[O3%NZDJ.png alt=7Q[G4PYYU6I{UAZ[O3%NZDJ.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/008967DC195A3C7B295FCCC63EAB3DB1.png title=}V2FFJMDD78TE]3C3V9WTIP.png alt=}V2FFJMDD78TE]3C3V9WTIP.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/225BCF2544ADA9FC13F4BC26B300BDD0.png title=1%{1V1DQX{2@CJ0GRHDUT3O.png alt=1%{1V1DQX{2@CJ0GRHDUT3O.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/9EAD356AA1989248F835B4ED1DD7C6CD.png title=2U}2`G}NI6FFW56A~ZJS4VY.png alt=2U}2`G}NI6FFW56A~ZJS4VY.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/53CF3E4DEF65390CE2882F63044246E1.png title=KJ9I9X300F[75LPM`0_GGTF.png alt=KJ9I9X300F[75LPM`0_GGTF.png/>