Internal
problem
ID
[8798]
Book
:
Own
collection
of
miscellaneous
problems
Section
:
section
1.0
Problem
number
:
86
Date
solved
:
Friday, April 25, 2025 at 05:10:15 PM
CAS
classification
:
[[_2nd_order, _exact, _nonlinear], [_2nd_order, _with_linear_symmetries], [_2nd_order, _reducible, _mu_x_y1], [_2nd_order, _reducible, _mu_y_y1], [_2nd_order, _reducible, _mu_xy]]
Time used: 35.829 (sec)
Solve
An exact non-linear second order ode has the form
Where the following conditions are satisfied
Looking at the the ode given we see that
Applying the conditions to the above shows this is a nonlinear exact second order ode. Therefore it can be reduced to first order ode given by
Which results in
Which is now solved.
In canonical form, the ODE is
An ode of the form
In this case, it can be seen that both
Applying the
transformation
Or
Or
Which is now solved as separable in
The ode
is separable as it can be written as
Where
Integrating gives
We now need to find the singular solutions, these are found by finding for what values
for
Now we go over each such singular solution and check if it verifies the ode itself and any initial conditions given. If it does not then the singular solution will not be used.
Therefore the solutions found are
Converting
Converting
Converting
Which simplifies to
Will add steps showing solving for IC soon.
Summary of solutions found
Time used: 36.862 (sec)
Solve
Writing the ode as
Integrating both sides of the ODE w.r.t
Which is now solved for
An ode of the form
In this case, it can be seen that both
Applying the
transformation
Or
Or
Which is now solved as separable in
The ode
is separable as it can be written as
Where
Integrating gives
We now need to find the singular solutions, these are found by finding for what values
for
Now we go over each such singular solution and check if it verifies the ode itself and any initial conditions given. If it does not then the singular solution will not be used.
Therefore the solutions found are
Converting
Converting
Converting
Which simplifies to
In canonical form, the ODE is
An ode of the form
In this case, it can be seen that both
Applying the
transformation
Or
Or
Which is now solved as separable in
The ode
is separable as it can be written as
Where
Integrating gives
We now need to find the singular solutions, these are found by finding for what values
for
Now we go over each such singular solution and check if it verifies the ode itself and any initial conditions given. If it does not then the singular solution will not be used.
Therefore the solutions found are
Converting
Converting
Converting
Which simplifies to
Will add steps showing solving for IC soon.
ode:=diff(diff(y(x),x),x) = 1/y(x)-x/y(x)^2*diff(y(x),x); dsolve(ode,y(x), singsol=all);
Maple trace
Methods for second order ODEs: --- Trying classification methods --- trying 2nd order Liouville trying 2nd order WeierstrassP trying 2nd order JacobiSN differential order: 2; trying a linearization to 3rd order trying 2nd order ODE linearizable_by_differentiation trying 2nd order, 2 integrating factors of the form mu(x,y) trying differential order: 2; missing variables -> trying 2nd order, dynamical_symmetries, fully reducible to Abel through one \ integrating factor of the form G(x,y)/(1+H(x,y)*y)^2 --- trying a change of variables {x -> y(x), y(x) -> x} and re-entering meth\ ods for dynamical symmetries --- -> trying 2nd order, dynamical_symmetries, fully reducible to Abel through o\ ne integrating factor of the form G(x,y)/(1+H(x,y)*y)^2 trying 2nd order, integrating factors of the form mu(x,y)/(y)^n, only the sing\ ular cases trying symmetries linear in x and y(x) trying differential order: 2; exact nonlinear -> Calling odsolve with the ODE, diff(_b(_a),_a) = -(_C1*_b(_a)-_a)/_b(_a), _b( _a) *** Sublevel 2 *** Methods for first order ODEs: --- Trying classification methods --- trying a quadrature trying 1st order linear trying Bernoulli trying separable trying inverse linear trying homogeneous types: trying homogeneous D <- homogeneous successful <- differential order: 2; exact nonlinear successful
ode=D[y[x],{x,2}]==1/y[x]-x/y[x]^2*D[y[x],x]; ic={}; DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
from sympy import * x = symbols("x") y = Function("y") ode = Eq(x*Derivative(y(x), x)/y(x)**2 + Derivative(y(x), (x, 2)) - 1/y(x),0) ics = {} dsolve(ode,func=y(x),ics=ics)
NotImplementedError : The given ODE Derivative(y(x), x) - (-y(x)*Derivative(y(x), (x, 2)) + 1)*y(x)/x cannot be solved by the factorable group method