Systems of ODE: Converting complex solution to real

In summary, the conversation is about finding a general solution to a system of linear first order ODE's. The solution is given as X = c1v1e^(-1+2i)t + c2v2e^(-1-2i)t, where v1 and v2 are given vectors. The question is how to convert this solution into its real equivalent. The person suggests resolving the solution into real and imaginary parts, but the other person is unsure if this will still span the solution space. They ask for a step by step explanation on how to convert the solution to its real form.
  • #1
Shaybay92
124
0

Homework Statement



So, I have found a general solution to a system of linear first order ODE's and this is what I got:

X = c1v1e^(-1+2i)t + c2v2e^(-1-2i)t

where v1 = [-1+2i, 5], v2=[-1-2i,5]. The question is, how do I now change this solution into its real equivalent? i.e. I don't want any complex numbers in my solution.

I have a textbook which explains but it still doesn't make sense to me how they manage to go from a complex to real solution. Could someone explain step by step? Thanks.
 
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  • #2
I think they're saying that X=x+yi, just resolve in real and imaginary parts...
 
  • #3
I don't think so, because it has to still span the solution space, and merely dropping the imaginary parts will not ensure this.
 

1. How do I convert a complex solution to a real solution for a system of ODEs?

To convert a complex solution to a real solution for a system of ODEs, you will need to use the technique of taking the real part of the complex solution. This involves separating the solution into its real and imaginary components, and then discarding the imaginary component to obtain the real solution.

2. Can I use Euler's formula to convert a complex solution to a real solution?

Yes, Euler's formula (e^(ix) = cos(x) + i*sin(x)) can be used to convert a complex solution to a real solution for a system of ODEs. By replacing the complex variables with their equivalent real and imaginary components, you can obtain a real solution.

3. Are there any other methods for converting complex solutions to real solutions for systems of ODEs?

Yes, apart from taking the real part or using Euler's formula, there are other methods for converting complex solutions to real solutions. These include using the trigonometric identities and the method of undetermined coefficients.

4. Is it always necessary to convert a complex solution to a real solution for systems of ODEs?

No, it is not always necessary to convert a complex solution to a real solution for systems of ODEs. In some cases, the complex solution may provide the most accurate and meaningful representation of the system's behavior. However, if you need to interpret the solution in terms of real-world quantities, converting it to a real solution may be necessary.

5. Can I convert a complex solution to a real solution for any system of ODEs?

In general, yes, you can convert a complex solution to a real solution for any system of ODEs. However, the process may become more complicated for systems with a large number of equations and variables. In these cases, it may be more efficient to use numerical methods to find the real solution instead of converting the complex solution.

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