function lineareq
    f=dsolve('D3y+4*Dy=10*exp(x)*(cos(x)-sin(x))','y(0)=1','Dy(0)=1','D2y(0)=2','x');
    s=-5:0.01:5;
    g=subs(f,'x',s);
    plot(s,g)
    M=max(g)
    m=min(g)

end

