Consider the integral equation
\[
u(x)-\lambda\int_{-1}^{1}\sum_{j=0}^{2}P_j(x)P_j(t)u(t)\,dt=f(x),
\qquad\text{for } -1\le x\le 1,
\]
where \(P_j(x)\) is the \(j\)th Legendre function.
**(a)** For which values of \(\lambda\) does the integral equation have a unique solution?
**(b)** Calculate this solution for the case that \(f(x)=x^2+1\).
Question
Math 6420 • PDE
Fall 1995 • Question 4