不求导?
估计不好办吧!
f‘(x)=3x^2-6x
令f‘(x)=0,x=±√2
当x＜-√2或x＞√2时,f‘(x)＞0,f(x)单增；当-√2＜x＜√2时,f’(x)＜0,f(x)单减