设函数在有界闭区域上连续，则是的https://img-ph-mirror.nosdn.127.net/AzSolBHpAcwrMwJeuCZ3qw==/6608821346933715540.pnghttps://img-ph-mirror.nosdn.127.net/7fwte4zRVRFsQA6AJGLNzQ==/6599274287471067843.pnghttps://img-ph-mirror.nosdn.127.net/JP8UrBsuml645rOhx1gFcw==/6608897213236161833.pnghttps://img-ph-mirror.nosdn.127.net/O_G3pHt3KyUzaRcmaobAmg==/6608234207725603267.png