Are the solutions to first order ODE's the same or different for x=a?

In summary, the conversation discusses two first order ODEs, y'(x)g(x)=0 and y'(x)g(x)=\delta (x-a), and their solutions, y(x)=C and y(x)= C+ \int dx \frac{\delta (x-a)}{g(x)}, respectively. It is noted that the two equations are equal except at x=a, but the solutions are different due to the presence of the Dirac delta function. The second solution also depends on the form of g(x), while the first does not. However, at x=a, the two ODEs are completely equal. The conversation also mentions the use of different constants (C and C') in the solutions, but notes
  • #1
mhill
189
1
Let be the first order ODE's

[tex] y'(x)g(x)=0 [/tex] and [tex] y'(x)g(x)=\delta (x-a) [/tex]

except when x=a the two equations are equal , however the solutions are very different

[tex] y(x)=C [/tex] and [tex] y(x)= C+ \int dx \frac{\delta (x-a)}{g(x)} [/tex]

or using the properties of Dirac delta [tex] y(x)=C+\frac{1}{g(a)} [/tex]

the second equation depends on the form of g(x) whereas the first does not, however except at the point x=a the 2 ODE's are completely equal.
 
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  • #2
Why are you saying the two solutions are different? You should be writing C for one and, say, C' for the other- the two constants are not necessarily the same. In fact, all you are saying is that C= C'+ 1/g(a). Which is perfectly reasonable since 1/g(a) is itself a constant.
 

1. Are all first order ODE solutions the same for x=a?

No, the solutions to first order ODEs can vary depending on the initial conditions and the specific ODE being solved.

2. Can the solutions to first order ODEs be different for different values of x=a?

Yes, the solutions can vary for different values of x=a, as the solution can be dependent on the specific value of the independent variable.

3. Are there any special cases where the solutions to first order ODEs are the same for x=a?

In some cases, the solutions to first order ODEs can be the same for x=a, such as when the ODE is linear and the initial conditions are identical.

4. What factors can affect the solutions to first order ODEs for x=a?

The solutions to first order ODEs can be affected by the initial conditions, the specific ODE being solved, and the value of x=a.

5. Is there a general method for finding the solutions to first order ODEs when x=a?

Yes, there are various methods for finding solutions to first order ODEs, such as separation of variables, integrating factors, and substitution methods. However, the specific method used may vary depending on the ODE and the initial conditions.

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