设<img src="https://static.zxtiku.com/wangke/imgs/topic/e497f171758736c5394e817453f5b821.jpg"/>在闭区间<img src="https://static.zxtiku.com/wangke/imgs/topic/6733ad27be98a5d76483a80f8286dda0.jpg"/>上连续，则<img src="https://static.zxtiku.com/wangke/imgs/topic/b24da4865e84c9373d8bbeec06a7dbdc.jpg"/>___.