若<img class=jc-formula data-tex=f\left( x \right) src=https://huaweicloudobs.ahjxjy.cn/FB6E53A56CB8DA138AA7D1A4EBCF7519.png style=vertical-align: middle;/>在<img class=jc-formula data-tex=\left[ a,b \right] src=https://huaweicloudobs.ahjxjy.cn/F7E2D96607BB44F0EF21CEDD74AA3D39.png style=vertical-align: middle;/>上具有三阶连续导数,且在<img class=jc-formula data-tex={ x }_{ 0 } src=https://huaweicloudobs.ahjxjy.cn/ABCC8DCF3CB54080A21570A5BADC633E.png style=vertical-align: middle;/><img class=jc-formula data-tex=\in \left( a,b \right) src=https://huaweicloudobs.ahjxjy.cn/54137EDF9AAE8C8988D2FF58BF9DBCD7.png style=vertical-align: middle;/>处,<img class=jc-formula data-tex=f^{ \prime }\left( { x }_{ 0 } \right) =f^{ \prime \prime }\left( { x }_{ 0 } \right) =0,f^{ \prime \prime \prime }\left( { x }_{ 0 } \right) \neq 0 src=https://huaweicloudobs.ahjxjy.cn/4EF25EC447EF6656029CF6BFD0E35F6F.png style=vertical-align: middle;/>,则( )
①
<img class=jc-formula data-tex=({ x }_{ 0 },f\left( { x }_{ 0 } \right) ) src=https://huaweicloudobs.ahjxjy.cn/A109C23827EC4A2A05876E108321A4C0.png style=vertical-align: middle;/>必是拐点<img class=jc-formula data-tex={ x }_{ 0 } src=https://huaweicloudobs.ahjxjy.cn/ABCC8DCF3CB54080A21570A5BADC633E.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=({ x }_{ 0 },f\left( { x }_{ 0 } \right) ) src=https://huaweicloudobs.ahjxjy.cn/A109C23827EC4A2A05876E108321A4C0.png style=vertical-align: middle;/>不是拐点
③
<img class=jc-formula data-tex=({ x }_{ 0 },f\left( { x }_{ 0 } \right) ) src=https://huaweicloudobs.ahjxjy.cn/A109C23827EC4A2A05876E108321A4C0.png style=vertical-align: middle;/>必为极值点