title: Multiplying by cumulative product within data frame
body: <p>I have one data.frame with four columns, T,Price, Adjustment_factor and Adjusted price. So with columns Price and Adjustment_factor I want to calculate Adjusted_price like table below.</p>
  
  <pre><code>T      Price     Adjustment_factor       Adjusted_price
  ----------------------------------------------------
  2010    78,974     1,000                      79,01
  2012    78,935     1,008                      78,97
  2013    78,294     1,081                      78,97
  2014    72,436     1,070                      78,97
  2015    67,700     1,000                      78,97
  </code></pre>
  
  <p>Formula for calculation Adjusted_price is not same for every row. </p>
  
  <pre><code>E.g For 2015  
           78,97 = 67,700 * (1,070 * 1,081 * 1,008 * 1,000)
      For 2014 
           78,97 =  72,436 * (1,081 * 1,008 * 1,000)
      For 2013 
          78,97 =  78,294 * ( 1,008 * 1,000)
  </code></pre>
  
  <p>Can anyone help me with some code for calculation?</p>