f := x -> x^sin(x):

Inflpts := [fsolve(D(D(f))(x), x=0..16, maxsols=6)];

Q := map(p->[p,f(p)], Inflpts):

T := seq(plot(D(f)(p)*(x-p)+f(p), x=p-1..p+1, color=red), p=Inflpts):

plots:-display(plot(f, 0.0..16.0, color=black), T,

        plots:-pointplot(Q, symbolsize=10, symbol=solidcircle, color=blue),

        map(p->plots:-textplot(evalf[4]([p[1]-sign(D(f)(p[1]))*2/3,p[2]+1,p]),

                               font=[Times,8]),Q), size=[800,400]);

a example fo infliction points, can be adjusted for find min/max  :to give a idea

with(Student[Basics]);
  [ExpandSteps, FactorSteps, LinearSolveSteps, LongDivision, 

    OutputStepsRecord, PracticeSheet, SolveSteps]

-----------------------------------------------------------------

FactorSteps(Y^2*x^3-x^3);  
How about for complex numbers ?

Given a polynome in C : z^4-2.z^3+ 3.z^2-2.z+2