$$\eqalign{
& y = {x^3} - 2{x^2} + x + 1 \cr
& TXD:\,\,\,D = R \cr
& y' = 3{x^2} - 4x + 1 = 0 \Leftrightarrow \left[ \matrix{
x = 1 \hfill \cr
x = {1 \over 3} \hfill \cr} \right. \cr
& BXD: \cr
& - \infty \,\,\, + \,\,\,{1 \over 3}\,\,\, - \,\,\,\,1\,\,\,\, + \,\, + \infty \cr
& \Rightarrow Ham\,\,so\,\,DB/\left( { - \infty ;{1 \over 3}} \right);\left( {1 + \infty } \right);\,\,NB/\left( {{1 \over 3};1} \right) \cr} $$
