3.2 Lösning 4f

\[\begin{array}{rcrcl} f'(x) & = & -9\,x^2 + 36\,x - 27 & = & 0 \\ & & x^2 - 4 \,x + 3 & = & 0 \end{array}\]

Vieta:

\[ \begin{array}{rcl} x_1 \cdot x_2 & = & 3 \\ x_1 + x_2 & = & -(-4) = 4 \\ &\Downarrow& \\ x_1 & = & 1 \\ x_2 & = & 3 \end{array}\]