(* 1° *)


NSolve[2 x^3 - 19 x^2 + 57x-53,x]

Plot[2 x^3 - 19 x^2 + 57x-53,{x,-10,10}]

FindRoot[2 x^3 - 19 x^2 + 57x-53,{x,5}]

(* 2° *)

Plot[10+x^2-2x+8Cos[3x],{x,-10,15}]

FindMinimum[10+x^2-2x+8Cos[3x],{x,11}]

(* 3° *)

b=1.0`50

c=4.0`50

NIntegrate[Cos[c x]Exp[-b x],{x,0,Pi},WorkingPrecision->50]

(* 4° *)

sol=NDSolve[{f''[x]+f'[x]+8f[x]==0,f[0]==0,f'[0]==1},f,{x,0,10}]

Plot[f[x]/.sol,{x,0,10}]

(* 5° *)

curva=Fit[Transpose[{xdata,ydata}],{1,x,x^2},x]

Plot[curva,{x,0,40}]