title: Convert output from symbolic math (sym) to float
body: <p>My question is similar to <a href="https://stackoverflow.com/questions/11114101/how-to-convert-mupad-symbol-i-sqrt-1-to-i-in-matlab/11114959#11114959">this question</a> but I believe it to be more general.<br>
  I use Matlab's symbolic math toolbox to solve an equation:  </p>
  
  <pre><code>MAZ = 0.5;
  MAU = 1.0;
  XI = 1.0;
  ALPHA = 2.0;
  
  DRG = 0.5;
  SRG = 1.0;
  
  PHI = 1 / (2 * MAU);
  
  syms L;
  
  f = 1 - DRG - sqrt(1 + (ALPHA * XI - L / (2 * XI * PHI) ) ^ 2 ) / ...
      sqrt(1 + (ALPHA * XI) ^ 2) + L / (4 * PHI * SRG * sqrt(1 + (ALPHA * XI)^2));
  
  a = solve(f,L,'Real',true);
  </code></pre>
  
  <p>The answer is:  </p>
  
  <pre><code>a =
  5^(1/2)/3 + (10*((4*5^(1/2))/25 + 6/25)^(1/2))/3 + 8/3
  5^(1/2)/3 - (10*((4*5^(1/2))/25 + 6/25)^(1/2))/3 + 8/3  
  </code></pre>
  
  <p>How do I automatically convert these expressions for <code>a</code> - which do not contain any symbolic expressions - to floats so that I can access them later in my code?</p>