Questions tagged [singular-solution]
For questions about the singular solution of the ordinary differential equations. It is a special type of solution different from general solution. Such solutions does not contain any arbitrary constant and is not a particular case of the general solution.
101 questions
2 votes
0 answers
55 views
Is there a way to rewrite a differential equation to obtain uniqueness? Lipschitz
Motivation: I am trying to find and plot the Geodesics on the Torus, and obtained the following ODE: $$ \dot{\theta}(\varphi)=f_P(\theta) \qquad f_P(\theta)=\frac{1}{Pr}(R+r\cos\theta)\sqrt{(R+r\cos\...
18 votes
6 answers
646 views
How to solve $\frac{dy}{dx}=xy^{1/2}, y(0)=0$?
On page 48 of [Zill2022], there is an initial-value problem (IVP): $$ \frac{dy}{dx}=xy^{1/2}, y(0)=0. \tag{1} $$ I try to solve this IVP by myself. My solution is as follows: Solution: First, it is ...
1 vote
1 answer
66 views
Is it a must for a singular solution to have the dependent variable in it in case of PDE?
Exercise Question given in text book : For the question (ii) here, from the equation $(2)$, we could eliminate $a$ and $b$ and say that $xy=1$ is the singular solution. But that was not done here. As ...
0 votes
0 answers
67 views
Comparison of exact and perturbed limits of solving a PDE
I have the following 'nonlinear heat equation' where I am trying to compare the exact solution with the answer which one would get using lowest-order perturbation theory: $$ {\frac {\partial }{\...
1 vote
1 answer
81 views
How to solve this Clairaut-type PDE: $z = 3x p + 3y q + \frac{1}{p q z^6}$?
I'm trying to solve the following partial differential equation: $$z= 3x \frac{\partial z}{\partial x} + 3y \frac{\partial z}{\partial y} + \frac{1}{\frac{\partial z}{\partial x} \frac{\partial z}{\...
1 vote
0 answers
106 views
Recurrence relations with singularities
Consider the following recurrence relation $$-2A_{n-1} + (n-1)A_{n+1} + (2-n^2) A_{n} =0$$ Notice that in this recurrence relation there is a singularity at $n=1$. I was wondering if these recurrence ...
1 vote
0 answers
51 views
Intersections of degenerate eigenvalue surfaces for a parametrized symmetric real matrix
Suppose I have a real symmetric $M\times M$ matrix whose matrix elements are parameterized by linear functions $$A_{ij}(x_1,\cdots,x_N) = \sum_{n=1}^N c_n^{ij} x_n.$$ For fixed real coefficients $c_n^{...
0 votes
1 answer
90 views
ODE with additional parameter - Comparison of various limiting solutions
I am trying to solve the following ODE, where s is the independent variable, and k is a parameter $$ \left( {\frac {{\rm d}^{2}}{{\rm d}{s}^{2}}}T \left( s \right) \right) {s}^{3}+ \left( -2\,k{s}^{...
2 votes
1 answer
327 views
Why p-discriminant method for finding singular solution does not produce the same singular solution as d'Alembert method?
I am learning the p-discriminant method for finding singular solutions for non-linear first order ODE's. But in this example ode, which is d'Alembert ODE, when using standard d'Alembert method for ...
1 vote
1 answer
86 views
Particular solution $x'=Ax+\cos(\alpha t)d+\sin(\alpha t)d $
Let be $A\in R^{n \times n},x_0,c,d\in R^n$ and $\alpha \in R-\{0\}$. Prove that the system $$x'=Ax+\cos(\alpha t)c+\sin(\alpha t)d $$ $$x(0)=x_0$$ has a particular solution of the form $\varphi_p(t)=\...
0 votes
1 answer
87 views
How to find the matrix $A$ from $C_0=A \times B$ or $C_1=B \times A$, given the singluar matrix B.
Kindly help me in the following: Let $C_0=A \times B$ and $C_1=B \times A$, where $A$ is a full rank square matrix, $B$ is a non-zero singular square matrix. Entries in $A,B,C$ are from finite ...
2 votes
0 answers
456 views
How to get a Filippov solution?
Recently, I read a book ISSN 2195-9862 about the Filippov theory. There is a differential inclusion $$\dot{x}\in F(x)=\begin{cases} -1&x>0\\ [-1,1]&x=0\\ 1&x<0 \end{cases}\\ x(t_0)=...
1 vote
1 answer
72 views
Obtaining correct boundary conditions around a pole for Bessel equation plus delta function
Consider the following Bessel-like equation: $$\frac{\partial^2u}{\partial \rho^2}+\frac{1}{\rho}\frac{\partial u}{\partial \rho}+u=\frac{A}{\rho}\delta(\rho) $$ Here, $\rho$ is non negative. This ...
0 votes
0 answers
86 views
Why do we need to keep the solution of the homogeneous equation in the general equation?
On the theme of differential equations, I wonder why we still need to keep the solution of the homogeneous equation. For example the linear differential equation : $y' + ay = x^2 \enspace \enspace \...
0 votes
0 answers
444 views
Find the singular solution of the differential equation $4x(\frac{dy}{dx})^2=(3x-1)^2.$
Find the singular solution of the differential equation $$4xp^2=(3x-1)^2,$$ where $p=\frac{dy}{dx}.$ As we know the singular solution, of a first order differential equation, is represented by the ...