title: Reading a cell value that contains a formula returns 0.0 when using xlrd
body: <p>I try to read a cell value, say E5 and E5 in the excel sheet contains a formula '<strong>=(A29 - A2)</strong>'. I use the following code and it returns me 0.00 instead of the actual value <strong>1.440408</strong>
  . Is there a way to solve this? I want to print the correct value. Please help me with this. Thank you.</p>
  
  <pre><code>book = xlrd.open_workbook('Test.xlsx')
  first_sheet = book.sheet_by_index(0)
  particular_cell_value = (first_sheet.cell_value(4,4))
  print(particular_cell_value)
  </code></pre>