Determining eigenfunctions + arbritary value constant

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SUMMARY

Determining eigenfunctions of differential equations does not necessitate the inclusion of an arbitrary constant in the solution. The arbitrary nature of this constant allows for its inclusion or exclusion based on the context of the problem. For linear differential equations, the general solution typically contains an arbitrary term, which can be specified by boundary conditions. For instance, the equation dx/dt + x = 0 has a general solution of x(t) = C e^{-t}, which becomes x(t) = e^{-t} when the initial condition x(0) = 1 is applied.

PREREQUISITES
  • Understanding of linear differential equations
  • Familiarity with eigenfunctions and eigenvalues
  • Knowledge of boundary value problems
  • Basic calculus, specifically differential equations
NEXT STEPS
  • Study the method of solving linear differential equations
  • Learn about boundary value problems and their significance
  • Explore the concept of eigenvalues in depth
  • Investigate the role of initial conditions in determining particular solutions
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Mathematicians, physicists, and engineering students focusing on differential equations, eigenvalue problems, and boundary conditions will benefit from this discussion.

JamesGoh
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When we determine an eigenfunction of a given differential equation, is it necessary to include the arbirtary value in front of the solution ?

If not, is it because of the term's arbritary nature which means we can choose to include/reject it from the determined eigenfunction ?
 
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If a differential equation allows for multiple solutions, the most general solution may contain an arbitrary term. This is always the case for linear equations, for example.

If, in addition, boundary conditions are given, then the arbitrary constant is set by those conditions.

As a basic example, the equation

\frac{dx}{dt} + x = 0

has a general solution

x(t) = C e^{-t}

but if an initial condition, e.g. x(0) = 1 is given, then the constant is set, and the particular solution for this inital value problem is

x(t) = e^{-t}
 

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