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A <img src="https://www.beizhujiaoyu.com/uploads/202208/160991592635311.png" width="19" height="52" /> B -<img src="https://www.beizhujiaoyu.com/uploads/202208/160991593194241.png" width="19" height="52" /> C 3 D -3

A (0，0) B (1，2) C (-1，2) D (-1，-2)

A yxy-1dx+xylnxdy B xy-1dx+ydy C xy(dx+dy) D xy(xdx+ydy)

A <img src="https://www.beizhujiaoyu.com/uploads/202208/160991735310951.png" width="70" height="33" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/160991735874531.png" width="113" height="33" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/160991736263731.png" width="63" height="33" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/160991736692661.png" width="70" height="33" />

A <img src="https://www.beizhujiaoyu.com/uploads/202208/160991658743371.png" width="82" height="34" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/160991659168091.png" width="63" height="33" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/1609916594881.png" width="69" height="34" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/160991659960711.png" width="73" height="33" />

A <img src="https://www.beizhujiaoyu.com/uploads/202208/16099173972321.png" width="107" height="34" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/160991740118351.png" width="159" height="34" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/160991740717361.png" width="77" height="30" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/160991741125851.png" width="67" height="34" />

A <img src="https://www.beizhujiaoyu.com/uploads/202208/160991737563151.png" width="15" height="30" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/160991737988521.png" width="15" height="30" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/160991738415811.png" width="34" height="30" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/160991738988321.png" width="37" height="27" />

A <img src="https://www.beizhujiaoyu.com/uploads/202208/160991597899911.png" width="27" height="52" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/16099159847701.png" width="27" height="52" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/160991598832111.png" width="19" height="52" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/16099159942651.png" width="20" height="52" />

A 0 B 1 C <img src="https://www.beizhujiaoyu.com/uploads/202208/160991730558691.png" width="20" height="52" /> D 2