圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/ScreenHunter_01Oct021156.gif
(http://i707.photobucket.com/albums/ww74/stevieg90/ScreenHunter_01Oct021156.gif)
更新1:
How about the part "if f(x) is cts on (0,3), prove that it is also cts on [1,2]"?
