单调区间与极值:y'=3x^2-4x+1=(3x-1)(x-1)显然x>1或x<1/3时y'>0函数单调递增在(1/3,1)区间内y'<0函数单调递减当x=1或1/3时y'=0函数取得极值y1=1/9,y2=7/27凹凸区间:y''=6x-4当x>2/3时y''>0函数凹当x<2/3时y''<0函数凸当x=2/3时y''=0函数拐点为(2/3,1/9)
