title: dividing a small number by a larger giving me 0.0
body: <p>I am doing a program that calculates radio activity at a previous point in time based on measured radioactivity.</p>
  
  <p>However if the half-life is very large compared with the elapsed time I get a <code>0.00</code> as the answer which then leaves me with <code>A= Ao</code> at least until <code>(times[i]-times[0])</code> gets large. </p>
  
  <p>For example if <code>(times[i]-times[0]) = 5</code> and <code>Thalflife = 6540</code> I want to get <code>0.00076452599</code> however I get <code>0.0</code> is double the wrong type to use or is it the <code>/</code> command that is giving me the problem?</p>
  
  <pre><code>private double[]theoreticalVals(double activity) {
     /* below is an implementation of the activity decay 
      * calculation formula A= Ao/2^(t/Thalflife)
      * An array of values will be returned. 
      * The times array defines the length of the array and gives the point in time values
      */
   double Ao= activity; 
   double [] vals = new double[times.length];
   double a; 
   vals[0]=Ao;                            //initial activity
   for(int i = 1; i&lt;times.length;i++){                
     a =(times[i]-times[0])/Hf;       //  
     double lowerhalfterm = Math.pow(.5,a);                   //  2-(^(t/Thalflife))
     vals[i]= Ao/lowerhalfterm;
  
  }                                          // A=Ao/2^(t/Thalflife)
  
  return vals; 
  }
  </code></pre>