f2[x_] := (x-3) Cos[2 x]

p2 = {Plot[f2[x],{x,-2,3}],
      Plot[f2'[x],{x,-2,3}]}

f3[x_] := x^2 Sin[2 x]

p3 = {Plot[f3[x],{x,-2,3}],
      Plot[f3'[x],{x,-2,3}]}

f4[x_] := x Sin[2 x]

p4 = {Plot[f4[x],{x,-2,3}],
      Plot[f4'[x],{x,-2,3}]}