title: PHP multiplication
body: <p>It is my first question, so hi all..</p>
  
  <p>Is it possible to satisfy this condition?
  Where $a and $b are some defined variables</p>
  
  <pre><code>if(!is_numeric($a * $b.'')) { ... }
  </code></pre>
  
  <p>EDIT: Second conditon</p>
  
  <pre><code>$a * $b can't be INF
  </code></pre>