Solving Problem with Derivatives as Initial Conditions

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SUMMARY

This discussion addresses solving differential equations with derivatives as initial conditions, specifically in the context of boundary value problems. The participant highlights the challenge of applying separation of variables when initial conditions are expressed as derivatives, such as x'(0)=0. The conclusion emphasizes that the solution involves using Fourier series to incorporate the initial conditions effectively, leading to a general solution of the form X(x) = c_1 cos(√λx), where λ represents the eigenvalue associated with the problem.

PREREQUISITES
  • Understanding of differential equations and boundary value problems
  • Familiarity with separation of variables technique
  • Knowledge of Fourier series and their application in solving differential equations
  • Basic concepts of eigenvalues and eigenfunctions in mathematical analysis
NEXT STEPS
  • Study the application of Fourier series in solving partial differential equations
  • Learn about the separation of variables method in greater detail
  • Explore the role of eigenvalues in boundary value problems
  • Review examples of differential equations with derivative initial conditions
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Students and educators in mathematics, particularly those focused on differential equations, boundary value problems, and mathematical analysis. This discussion is beneficial for anyone seeking to deepen their understanding of solving equations with derivative initial conditions.

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Homework Statement



I've been given equations that have derivatives as initial conditions, rather than things like u(0,t)=u(L,t)=0

Things like this:

http://img444.imageshack.us/img444/5082/mathu.th.jpg

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Homework Equations






The Attempt at a Solution


I can solve problems with condition like u(0,t)=u(L,t)=0 but how do you solve them with derivatives?

Wouldn't for lamba=0 X''=0 -> X=c1*x+c2 and applying x'(0)=0 make X=c2?
 
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You would follow the exact same process (of separation of variables).

The reason \lambda = 0 doesn't work is the same reason it doesn't work when you use the standard boundary conditions you've listed above.

The end result is you end up with an equation for X as X(x) = c_1 \cos{\sqrt{\lambda}x}. What does this say about \lambda? To finish the problem, you need to apply the idea of Fourier series and use your initial condition.
 

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