sage: f= 2*x^3-3*x^2-12*x+1 sage: df = diff(f,x) sage: df sage: solve(df,x)
sage: solve(df>0,x)
sage: ddf=diff(df,x) sage: ddf sage: [ddf.subs({x:-1}), ddf.subs({x:2})]
sage: solve(ddf>0,x)
sage: solve(ddf,x) sage: diff(ddf,x)
sage: plot(f, (-5,5), ymax=20, ymin=-20)