Differential equation problem

In summary, the conversation discusses finding the general solution of an Euler Cauchy equation, using the formula m(m-1) +am + b = 0. The first step is to find the values of m by equating the coefficients. The correct values for a and b are +1 and -1, respectively. The conversation also mentions the use of variation of parameters and the possibility of using undetermined coefficients or a change of variable to solve the equation.
  • #1
engineer_dave
35
0

Homework Statement



Find the general solution of x^2y" + xy' - y = 1/x


Homework Equations



m(m-1) +am + b = 0 to solve an Euler Cauchy equation

The Attempt at a Solution



a=1 b=-1

m(m-1) -m -1 =0

m^2 - 2m -1 = 0

I just want to know whether the first step is right. And once I find out the values of M, do I use variation of parameters to find the particular solution? Thanks
 
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  • #2
engineer_dave said:

Homework Statement



Find the general solution of x^2y" + xy' - y = 1/x


Homework Equations



m(m-1) +am + b = 0 to solve an Euler Cauchy equation

The Attempt at a Solution



a=1 b=-1

m(m-1) -m -1 =0

m^2 - 2m -1 = 0

I just want to know whether the first step is right. And once I find out the values of M, do I use variation of parameters to find the particular solution? Thanks
One obvious error: a= +1 here , not -1. Yes, you can use "variation of parameters". Also, because the right hand side is a power of x, you could use "undertermined coefficients" although it is slightly harder to "guess" the correct form for a particular solution in such an equation as compared to a "constant coefficients" equation. Finally, the change of variable u= ln(x) will convert this equation to a "constant coefficients" equation.
 

What is a differential equation?

A differential equation is a mathematical equation that describes the relationship between a function and its derivatives. It involves the use of derivatives, which represent the rate of change of a function, to model real-world phenomena.

What is the purpose of solving a differential equation?

The purpose of solving a differential equation is to determine the function that satisfies the equation and accurately predicts the behavior of a system. This can be used in various fields such as physics, engineering, and economics to understand and predict complex systems.

What are the different types of differential equations?

There are several types of differential equations, including ordinary differential equations (ODEs), partial differential equations (PDEs), and stochastic differential equations (SDEs). ODEs involve only one independent variable, while PDEs involve multiple independent variables. SDEs, on the other hand, incorporate random elements into the equation.

What techniques are used to solve differential equations?

The techniques used to solve differential equations depend on the type of equation. Some common methods include separation of variables, substitution, and using the integrating factor. For more complex equations, numerical methods such as Euler's method and the Runge-Kutta method may be used.

What are some applications of differential equations?

Differential equations have various applications in the fields of physics, engineering, finance, and biology. They are used to model and predict the behavior of systems such as population growth, heat transfer, and electrical circuits. They are also used in developing mathematical models for financial markets and biological systems.

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