5.1.2 Linear ode with non-constant coefficients

5.1.2.1 Euler type \(x^{3}y^{\prime \prime \prime }+x^{2}y^{\prime \prime }+xy^{\prime }+y=f\left ( x\right ) \)
5.1.2.2 Solved using reduction of order
5.1.2.3 Solved by finding first intergal (exact ode)
5.1.2.4 Solved by series method