设<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/e2669afa14654204888610d2975678c6.png?x-oss-process=image/sharpen,200"/>在<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/d099aba270c64437b2ebda89297ecbf9.png?x-oss-process=image/sharpen,200"/>的某邻域内有定义，且<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/d099aba270c64437b2ebda89297ecbf9.png?x-oss-process=image/sharpen,200"/>为<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/4548602d01444224b31c69133d6dcf79.png?x-oss-process=image/sharpen,200"/>的第一类间断点，为<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/787eaf61b7194646aa5f208ba8fdbd4e.png?x-oss-process=image/sharpen,200"/>的第二类间断点，则<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/d099aba270c64437b2ebda89297ecbf9.png?x-oss-process=image/sharpen,200"/>必为