El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left(- 6 x^{2} + \left(x^{4} - \frac{8 x^{3}}{3}\right)\right) + 1 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{2}{3} - \frac{\sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}{2} - \frac{\sqrt{\frac{104}{9} - 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}} - \frac{560}{27 \sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}} - \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}}{2}$$
$$x_{2} = \frac{2}{3} + \frac{\sqrt{\frac{104}{9} - 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}} - \frac{560}{27 \sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}} - \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}}{2} - \frac{\sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}{2}$$
$$x_{3} = \frac{2}{3} - \frac{\sqrt{\frac{104}{9} - 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}} + \frac{560}{27 \sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}} - \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}}{2} + \frac{\sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}{2}$$
$$x_{4} = \frac{2}{3} + \frac{\sqrt{\frac{104}{9} - 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}} + \frac{560}{27 \sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}} - \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}}{2} + \frac{\sqrt{\frac{52}{9} + \frac{8}{3 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}} + 2 \sqrt[3]{\frac{4}{9} + \frac{4 \sqrt{11} i}{9}}}}{2}$$
Solución numérica$$x_{1} = 4.11157447434758$$
$$x_{2} = 0.381475374124104$$
$$x_{3} = -0.470074660199517$$
$$x_{4} = -1.3563085216055$$