title: Numerical Solution for a specified parameter in NDSolve (Mathematica)
body: <p>I am working on a solution to solve a Partial Differential Equation, Fick's Second Law of Diffusion to be exact.
  I was able to produce a 3D Plot using the NDSolve and Plot3D functions. 
  Code used:</p>
  
  <pre><code>NDSolve[{D[c[t, h], t] == 1*D[c[t, h], h, h],
                 c[0, h] == Erfc[h/(2*81.2)], 
                 c[t, 0] == 1, 
              c[t, 4000] == 3.08*^-18}, c, {t, 0, 900}, {h, 0, 274}]
  </code></pre>
  
  <p>Instead of a graphical representation, I would like to find numerical points of the graph at t = 900.
  I would like to know how to put in t = 900 into NDSolve (or other functions) so as to generate detailed numerical points of the solution.</p>