podaci:={{0,2.1},{1,1.7},{2,3.2},{3,2.5}}
prikazpodataka:=ListPlot[podaci,PlotRange-> {{0,4},{0,4}},PlotStyle-> PointSize[0.03]]
Lagrange[x_]:=Expand[InterpolatingPolynomial[podaci,x]]
prikazLagrange:=Plot[Lagrange[x],{x,0,4}]
Show[prikazpodataka,prikazLagrange]
Lagrange[1.5]

f[x_]:=(x^4)+4(x^3)-7(x^2)-23x+23
Plot[f[x],{x,-10,10}]
NSolve[f[x]==0,x]

rjesenje:=NDSolve[{y'[x]==1-x^2*y[x],y[0]==1},y,{x,0,3}]
Plot[Evaluate[y[x]/.rjesenje],{x,0,3}]