title: Excel: How to write z=f(x,y) for different values of (x,y)
body: <p>Anyone can help me with this problem?
  I would like a way to write a formula z=f(x,y) and tell excel to calculate the value of that formula for different sets of the couple (x,y).</p>
  
  <p>Or I could do this but I don't know how: </p>
  
  <pre><code>CELL 1:x^2+y^2,x=A1,y=A2
  CELL 2:x^2+y^2,x=B1,y=B2
  CELL 3:x^2+y^2,x=C1,y=C2
  etc...
  </code></pre>
  
  <p>How can I do?
  Thanks in advance for your precious help</p>