## Calculus (3rd Edition)

$$y''=20x^3+12x^2+2, \quad y'''=60x^2+24x.$$
Let $y=(x^2+x)(x^3+1)$; first we simplify $y$ as follows $$y=(x^2+x)(x^3+1)=x^5+x^4+x^2+x.$$ Now, we get $$y'=5x^4+4x^3+2x+1$$ $$y''=20x^3+12x^2+2, \quad y'''=60x^2+24x.$$