title: Eigenvalues NaN and inf
body: <p>Suppose I have a system AX =  nBX where A and B are known martrices, X is the coefficient matrix. </p>
  
  <p>I am solving this using Chebyshev polynomials. </p>
  
  <p>BC's are u(-1)=0=u(1)</p>
  
  <p>I am imposing the bc's for the first and last rows of matrices A and B.</p>
  
  <pre><code>e=solve(A,B)
  
  e[1]=0
  
  e[-1]=0
  
  x=solve(A,e)
  </code></pre>
  
  <p>What is wrong with this?</p>