Internal problem ID [8432]
Internal file name [OUTPUT/7365_Sunday_June_05_2022_10_53_45_PM_60559200/index.tex]
Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 95.
ODE order: 1.
ODE degree: 1.
The type(s) of ODE detected by this program : "riccati"
Maple gives the following as the ode type
[_rational, _Riccati]
\[ \boxed {x y^{\prime }+y^{2}=-x^{2}} \]
In canonical form the ODE is \begin {align*} y' &= F(x,y)\\ &= -\frac {x^{2}+y^{2}}{x} \end {align*}
This is a Riccati ODE. Comparing the ODE to solve \[ y' = -x -\frac {y^{2}}{x} \] With Riccati ODE standard form \[ y' = f_0(x)+ f_1(x)y+f_2(x)y^{2} \] Shows that \(f_0(x)=-x\), \(f_1(x)=0\) and \(f_2(x)=-\frac {1}{x}\). Let \begin {align*} y &= \frac {-u'}{f_2 u} \\ &= \frac {-u'}{-\frac {u}{x}} \tag {1} \end {align*}
Using the above substitution in the given ODE results (after some simplification)in a second order ODE to solve for \(u(x)\) which is \begin {align*} f_2 u''(x) -\left ( f_2' + f_1 f_2 \right ) u'(x) + f_2^2 f_0 u(x) &= 0 \tag {2} \end {align*}
But \begin {align*} f_2' &=\frac {1}{x^{2}}\\ f_1 f_2 &=0\\ f_2^2 f_0 &=-\frac {1}{x} \end {align*}
Substituting the above terms back in equation (2) gives \begin {align*} -\frac {u^{\prime \prime }\left (x \right )}{x}-\frac {u^{\prime }\left (x \right )}{x^{2}}-\frac {u \left (x \right )}{x} &=0 \end {align*}
Solving the above ODE (this ode solved using Maple, not this program), gives
\[ u \left (x \right ) = c_{1} \operatorname {BesselJ}\left (0, x\right )+c_{2} \operatorname {BesselY}\left (0, x\right ) \] The above shows that \[ u^{\prime }\left (x \right ) = -c_{1} \operatorname {BesselJ}\left (1, x\right )-c_{2} \operatorname {BesselY}\left (1, x\right ) \] Using the above in (1) gives the solution \[ y = \frac {\left (-c_{1} \operatorname {BesselJ}\left (1, x\right )-c_{2} \operatorname {BesselY}\left (1, x\right )\right ) x}{c_{1} \operatorname {BesselJ}\left (0, x\right )+c_{2} \operatorname {BesselY}\left (0, x\right )} \] Dividing both numerator and denominator by \(c_{1}\) gives, after renaming the constant \(\frac {c_{2}}{c_{1}}=c_{3}\) the following solution
\[ y = -\frac {\left (c_{3} \operatorname {BesselJ}\left (1, x\right )+\operatorname {BesselY}\left (1, x\right )\right ) x}{c_{3} \operatorname {BesselJ}\left (0, x\right )+\operatorname {BesselY}\left (0, x\right )} \]
The solution(s) found are the following \begin{align*} \tag{1} y &= -\frac {\left (c_{3} \operatorname {BesselJ}\left (1, x\right )+\operatorname {BesselY}\left (1, x\right )\right ) x}{c_{3} \operatorname {BesselJ}\left (0, x\right )+\operatorname {BesselY}\left (0, x\right )} \\ \end{align*}
Verification of solutions
\[ y = -\frac {\left (c_{3} \operatorname {BesselJ}\left (1, x\right )+\operatorname {BesselY}\left (1, x\right )\right ) x}{c_{3} \operatorname {BesselJ}\left (0, x\right )+\operatorname {BesselY}\left (0, x\right )} \] Verified OK.
\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & x y^{\prime }+y^{2}=-x^{2} \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=-\frac {y^{2}+x^{2}}{x} \end {array} \]
Maple trace
`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 Chini differential order: 1; looking for linear symmetries trying exact Looking for potential symmetries trying Riccati trying Riccati sub-methods: trying Riccati to 2nd Order -> Calling odsolve with the ODE`, diff(diff(y(x), x), x) = -(diff(y(x), x))/x-y(x), y(x)` *** Sublevel 2 *** Methods for second order ODEs: --- Trying classification methods --- trying a quadrature 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 <- Riccati to 2nd Order successful`
✓ Solution by Maple
Time used: 0.0 (sec). Leaf size: 27
dsolve(x*diff(y(x),x) + y(x)^2 + x^2=0,y(x), singsol=all)
\[ y \left (x \right ) = -\frac {\left (c_{1} \operatorname {BesselY}\left (1, x\right )+\operatorname {BesselJ}\left (1, x\right )\right ) x}{c_{1} \operatorname {BesselY}\left (0, x\right )+\operatorname {BesselJ}\left (0, x\right )} \]
✓ Solution by Mathematica
Time used: 0.152 (sec). Leaf size: 45
DSolve[x*y'[x] + y[x]^2 + x^2==0,y[x],x,IncludeSingularSolutions -> True]
\begin{align*} y(x)\to -\frac {x (\operatorname {BesselY}(1,x)+c_1 \operatorname {BesselJ}(1,x))}{\operatorname {BesselY}(0,x)+c_1 \operatorname {BesselJ}(0,x)} \\ y(x)\to -\frac {x \operatorname {BesselJ}(1,x)}{\operatorname {BesselJ}(0,x)} \\ \end{align*}