Internal
problem
ID
[8833]
Book
:
Own
collection
of
miscellaneous
problems
Section
:
section
2.0
Problem
number
:
28
Date
solved
:
Wednesday, March 05, 2025 at 06:52:31 AM
CAS
classification
:
[[_2nd_order, _linear, _nonhomogeneous]]
Solve
Time used: 0.055 (sec)
This is Airy ODE. It has the general form
Where in this case
Therefore the solution to the homogeneous Airy ODE becomes
Since this is inhomogeneous Airy ODE, then we need to find the particular solution. The particular solution is now found using the method of undetermined coefficients. Looking at the RHS of the ode, which is
Shows that the corresponding undetermined set of the basis functions (UC_set) for the trial solution is
While the set of the basis functions for the homogeneous solution found earlier is
Since there is no duplication between the basis function in the UC_set and the basis functions of the homogeneous solution, the trial solution is a linear combination of all the basis in the UC_set.
The unknowns
Solving for the unknowns by comparing coefficients results in
Substituting the above back in the above trial solution
Therefore the general solution is
Will add steps showing solving for IC soon.
Summary of solutions found
Time used: 0.827 (sec)
In normal form the ode
Becomes
Where
The Lagrange adjoint ode is given by
Which is solved for
Where in this case
Therefore the solution to the homogeneous Airy ODE becomes
Will add steps showing solving for IC soon.
The original ode now reduces to first order ode
Or
Which is now a first order ode. This is now solved for
Comparing the above to the given ode shows that
The integrating factor
The ode becomes
Integrating gives
Dividing throughout by the integrating factor
Hence, the solution found using Lagrange adjoint equation method is
The constants can be merged to give
Will add steps showing solving for IC soon.
Summary of solutions found
ode:=diff(diff(y(x),x),x)-x*y(x)-x^3+2 = 0; dsolve(ode,y(x), singsol=all);
Maple trace
`Methods for second order ODEs: --- Trying classification methods --- trying a quadrature trying high order exact linear fully integrable trying differential order: 2; linear nonhomogeneous with symmetry [0,1] trying a double symmetry of the form [xi=0, eta=F(x)] -> Try solving first the homogeneous part of the ODE checking if the LODE has constant coefficients checking if the LODE is of Euler type trying a symmetry of the form [xi=0, eta=F(x)] checking if the LODE is missing y -> Trying a Liouvillian solution using Kovacics algorithm <- No Liouvillian solutions exists -> Trying a solution in terms of special functions: -> Bessel <- Bessel successful <- special function solution successful <- solving first the homogeneous part of the ODE successful`
ode=D[y[x],{x,2}]-x*y[x]-x^3+2==0; ic={}; DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
from sympy import * x = symbols("x") y = Function("y") ode = Eq(-x**3 - x*y(x) + Derivative(y(x), (x, 2)) + 2,0) ics = {} dsolve(ode,func=y(x),ics=ics)