Write a user-defined function to calculate a firm's return on equity using the Du Pont method as

Question:

Write a user-defined function to calculate a firm's return on equity using the Du Pont method as defined by (4-29) on page 123. You will need the function to accept three arguments: the net profit margin, total ratio, and the debt ratio.
Asset Turnover
Asset turnover is sales divided by total assets. Important for comparison over time and to other companies of the same industry. This is a standard business ratio.