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Question

Math 6420 • PDE

Spring 2013 • Question 2

  1. Specify the weak formulation for the differential equation \[ u''+\lambda \delta (x-1/2)u=f(x) \] subject to boundary conditions \(u(0)=u(1)=0\).
  2. Find all values of \(\lambda \) for which this differential equation with \(f(x)=0\) has a nontrivial solution and verify that the corresponding solution is a weak solution.
  3. Suppose \(\lambda \) is such that this differential equation with \(f(x)=0\) has only the trivial solution. Find the solution with \(f(x)=1\).

Raw LaTeX

\begin{enumerate}
\item[(a)] Specify the weak formulation for the differential equation
\[
  u''+\lambda\delta(x-1/2)u=f(x)
\]
subject to boundary conditions \(u(0)=u(1)=0\).

\item[(b)] Find all values of \(\lambda\) for which this differential equation with
\(f(x)=0\) has a nontrivial solution and verify that the corresponding solution is a weak
solution.

\item[(c)] Suppose \(\lambda\) is such that this differential equation with \(f(x)=0\) has only
the trivial solution. Find the solution with \(f(x)=1\).
\end{enumerate}