Differential Equation, Substitution?

In summary, we are tasked with finding the particular solution to the given differential equation, with the initial condition y=1 when x=4. The equation can be simplified by substituting z=y+x, but an analytic solution may not be possible and a numerical solution may reveal unusual behavior.
  • #1
vsportsguy
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Homework Statement


Find the particular solution to the differential equation
(x + y - 4)dx - (3x - y - 4)dy = 0
that satisfies the initial condition y=1 when x=4

Homework Equations


The Attempt at a Solution


It's not a homog. or equal D.E., therefore I think it's substitution. I don't really know how to get this problem started.
 
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  • #2
You can simplify the equation by substituting z = y + x. (Note that y = x is a solution for the initial condition x=1, y=1.) However, I don't think you'll be able to find an analytic solution. Numerical solution suggests some pretty funky behavior between 1.84 and 1.85.
 

FAQ: Differential Equation, Substitution?

What is a differential equation?

A differential equation is a mathematical equation that relates an unknown function to its derivatives. It describes the relationship between the rate of change of a function and the value of the function itself. Differential equations are used in many scientific and engineering fields to model various phenomena.

How is substitution used in differential equations?

Substitution is a technique in differential equations where a new variable is introduced to replace an existing variable in the equation. This allows for simplification of the equation and makes it easier to solve. Substitution can also be used to transform a differential equation into a different form, making it easier to solve or to find a solution.

What are the benefits of using substitution in differential equations?

Substitution allows for the simplification and transformation of differential equations, making them easier to solve. It can also lead to the discovery of new relationships between variables and help in understanding the behavior of a system described by the equation.

Are there different methods of substitution in differential equations?

Yes, there are different methods of substitution used in differential equations, such as the method of undetermined coefficients, the method of variation of parameters, and the Laplace transform method. Each method has its advantages and is used for different types of differential equations.

How important is substitution in solving differential equations?

Substitution is an essential technique in solving differential equations. It allows for the simplification and transformation of equations, making them easier to solve and understand. Many differential equations cannot be solved without using substitution, and it is a fundamental tool in the field of mathematics.

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