Homogenous Differential Equations (Converting Back into Explicit Form

In summary, the given equation can be solved by dividing everything by x dx and putting it in terms of v. After integrating both sides and using the initial condition, the explicit form of the equation is y = -x/(ln(cx)).
  • #1
checkmatechamp
23
0

Homework Statement



x*e^(y/x) + y dx = xdy, y(1) = 0

Homework Equations



The Attempt at a Solution



To solve, I divide everything by x dx to put everything in terms of v.

e^v + v = dy/dx

dy/dx = x dv/dx + v

e^v + v = x dv/dx + v

e^v = x dv/dx

e^v / dv = x/dx

Flip both sides.

e^-v dv = 1/x dx

Integrate both sides

-e^-v = ln|x| + c

-e^(-y/x) = e^(ln|x| + c)

-e^(-y/x) = x * e^c

-e^(-y/x) = cx

ln(-e^(-y/x)) = ln(cx)

ln(e^(x/-y)) = ln(cx)

-x/y = ln(cx)

1/y = -ln(cx)/x

y = -x/(ln(cx))

Is that the correct explicit form? Would it make it easier if I used the initial condition to find c, and then attempted to put it in explicit form, or not?
 
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  • #2
-e^-v = ln|x| + c

-e^(-y/x) = e^(ln|x| + c)

this step does not follow. otherwise I think you're on the right track.
 

Related to Homogenous Differential Equations (Converting Back into Explicit Form

1. What is a homogenous differential equation?

A homogenous differential equation is a type of differential equation in which all terms involve the dependent variable and its derivatives. In other words, there is no constant term or term that does not involve the dependent variable.

2. How do you convert a homogenous differential equation into explicit form?

To convert a homogenous differential equation into explicit form, you can use the substitution method. First, let u = y/x, then replace all instances of y and y' with ux and u'x + u respectively. This will result in a separable differential equation that can be solved using standard techniques.

3. What is the purpose of converting a homogenous differential equation into explicit form?

Converting a homogenous differential equation into explicit form can make it easier to solve and understand. It can also help identify any possible singular solutions. Additionally, it allows for the use of standard techniques for solving differential equations, such as separation of variables or integrating factors.

4. Are there any special cases when converting a homogenous differential equation into explicit form?

Yes, there are special cases in which the substitution method may not work. These include when the equation is not homogeneous, when the equation is of higher order, or when there are singular solutions. In these cases, alternative methods may need to be used.

5. Can a homogenous differential equation be solved without converting it into explicit form?

Yes, there are other methods for solving homogenous differential equations, such as the method of undetermined coefficients or the method of variation of parameters. However, converting the equation into explicit form can often make the solution process simpler and more straightforward.

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