Categorize first order differential equation

In summary, the ODE given is a separable equation and can be solved using the method of separation of variables.
  • #1
BlueSocks
2
0

Homework Statement


I'm trying to determine which categories various first order differential equations fall into (and once they're categorized they're nice and easy to solve). My list of categories is the following; linear equations, homogenous equations, bernoulli equations, exact equations, exact equations with special integrating factors, separable equations, equations with linear coefficients, and equations that fit the form y'=g(ax+by).

However, I can't seem to transform the following equation into anything that would fit any of the above.

dy/dx=-y2/(x2 + 4xy)


The Attempt at a Solution



I've tried transforming the equation in pretty much every way I can think of, but I'm not finding any readily solvable form. the closest I've gotten (I think) is y' =(x2/y2 - 4x(1/y))-1 but other than isolating y' (in a different way), that doesn't seem to be much good. Am I missing something obvious here? Sorry, I feel a little silly. If that's not enough attempt at a solution I can show my work for all the other forms of the equation that I've worked to.

Thank you very much for any direction/assistance you might provide.


Cheers!
 
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  • #2
BlueSocks said:

Homework Statement


I'm trying to determine which categories various first order differential equations fall into (and once they're categorized they're nice and easy to solve). My list of categories is the following; linear equations, homogenous equations, bernoulli equations, exact equations, exact equations with special integrating factors, separable equations, equations with linear coefficients, and equations that fit the form y'=g(ax+by).

However, I can't seem to transform the following equation into anything that would fit any of the above.

dy/dx=-y2/(x2 + 4xy)

Doesn't that fit your category M and N are homogeneous of degree 2?
 
  • #3
...yup. Well, I feel incredibly silly all of a sudden. Thank you, I really appreciate you pointing that out. I think I'll be good from here on in.
 
  • #4
Indeed, the ODE can be written in the form [tex]\frac{dy}{dx}=f\left(\frac{y}{x}\right)[/tex]
 

Related to Categorize first order differential equation

1. What is a first order differential equation?

A first order differential equation is an equation that involves one independent variable (usually denoted as x) and the first derivative of the dependent variable (usually denoted as y). It can be written in the form dy/dx = f(x,y), where f(x,y) is a function of x and y.

2. How do you categorize a first order differential equation?

A first order differential equation can be categorized into three types: separable, linear, and exact. A separable differential equation can be written in the form dy/dx = g(x)h(y), where g(x) and h(y) are functions. A linear differential equation can be written in the form dy/dx + p(x)y = g(x). An exact differential equation can be written in the form M(x,y)dx + N(x,y)dy = 0, where M and N are functions of x and y.

3. How do you solve a separable differential equation?

To solve a separable differential equation, first separate the variables (x and y) and then integrate both sides. This will give you the general solution. To find the particular solution, use the initial conditions given in the problem.

4. What is the difference between a linear and an exact differential equation?

The main difference between a linear and an exact differential equation lies in their form. A linear differential equation has the form dy/dx + p(x)y = g(x), while an exact differential equation has the form M(x,y)dx + N(x,y)dy = 0. Additionally, a linear differential equation can be solved using integration methods, while an exact differential equation requires the use of partial derivatives.

5. Can a first order differential equation have more than one solution?

Yes, a first order differential equation can have more than one solution. This is because the general solution of a differential equation contains a constant (known as the arbitrary constant) that can take on different values, resulting in different solutions. The particular solution, determined by the initial conditions, will be the unique solution to the differential equation.

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