title: MATLAB examples are failing
body: <p>I don't have the slightest idea what's going on here, and Google provides no interesting help. I took the following example from <a href="http://www.mathworks.com/help/toolbox/symbolic/solve.html#inputarg_eqn" rel="noreferrer">http://www.mathworks.com/help/toolbox/symbolic/solve.html#inputarg_eqn</a></p>
  
  <pre><code>&gt;&gt; syms x
  &gt;&gt; solve(x^2 + 4*x + 1 == 0)
  ??? Error using ==&gt; char
  Conversion to char from logical is not possible.
  
  Error in ==&gt; solve&gt;getEqns at 169
     vc = char(v);
  
  Error in ==&gt; solve at 67
  [eqns,vars] = getEqns(varargin{:});
  </code></pre>
  
  <p>What's going on here?</p>