x^5 -x^4 +4*x^3 -3*x^2 +4*x -3
= (x - 0.7626918603256712159)
* (x*x -0.6100038387443596*x +2.4229341986697917)
* (x*x +0.37269569907003080*x +1.6234186219278017)

実根　 0.7626918603256712159

複素根　0.3050019193721798 ± 1.5264036254703662*i
　　　 -0.1863478495350154 ± 1.2604336955593805*i