Differential equation help solving homogeneous equations

In summary, the conversation discusses finding a general solution or implicit relation for the equation xy'-y=x tan(y/x). It includes an attempt at a solution using substitution and integration, with the final answer being y[x] = x*(ArcSin[(e^c)*x]). The conversation also mentions the importance of separating variables when solving this type of equation.
  • #1
Jim4592
49
0

Homework Statement



Find a general solution if possible, otherwise find a relation that defines the solutions implicity.

xy'-y=x tan(y/x)

Homework Equations





The Attempt at a Solution



y'-(y/x) = tan(y/x)

v = y/x ; y = xv ; y' = xv' + v

xv' + v = tan(v) + v

xv' = tan(v)

I got stuck there I'm not exactly sure how to integrate [tan(v)/x] to get v
and once i get v I'm not sure what to do to get y.

from using mathmatica command DSolve[xy'[x]-y[x]==xTan[y[x]/x],y[x],x] i got an answer of:

y[x] = x*(ArcSin[(e^c)*x])

Any help will be much appreciated!
 
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  • #2
Don't try to integrate tan(v)/x. You've got x*dv/dx=tan(v). Separate the variables. dv/tan(v)=dx/x. Integrate both sides.
 
  • #3
thanks! i forgot all about separating variables! it was so much easier once i did that. i ended up getting the answer, thanks again!
 

1. What is a homogeneous differential equation?

A homogeneous differential equation is a type of differential equation where all the terms involve the dependent variable and its derivatives. In other words, the equation can be expressed in the form of F(x, y, y', y'', ... ,y(n)) = 0, where y is the dependent variable and x is the independent variable.

2. How do you solve a homogeneous differential equation?

To solve a homogeneous differential equation, you can use the method of separation of variables, where you separate the variables and integrate both sides. Alternatively, you can use the substitution method, where you substitute y = vx or y = ux^n to reduce the equation into a separable form.

3. What is the order of a homogeneous differential equation?

The order of a homogeneous differential equation is the highest order of the derivative present in the equation. For example, the equation y'' + 3y' + 2y = 0 is a second-order homogeneous differential equation.

4. Can a homogeneous differential equation have non-constant coefficients?

Yes, a homogeneous differential equation can have non-constant coefficients. However, to be considered homogeneous, the equation must satisfy the condition that all the terms involve the dependent variable and its derivatives. So, even if the coefficients are not constant, the equation can still be homogeneous.

5. What is the general solution of a homogeneous differential equation?

The general solution of a homogeneous differential equation is a family of functions that satisfies the equation. It contains all possible solutions and can be obtained by solving the equation using the methods mentioned in question 2. The general solution will also contain one or more arbitrary constants, which can be determined by applying initial or boundary conditions.

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