for net income growth and sales growth what us the ^(1/4)-1? where did it came from!?

DEV x fx ={D7/D3)^(1/4)-1 A B D x Change in Sales Change in Net Income Part A First Year 2016 2017 2018 2019 2020 Sales(5000's) 546000 576000 680000 1050000 1150000 Net Profit Margin 0.058 0.068 0.055 0.038 0.034 Net Income 31668 39168 37400 39900 39100 5,49% 18.06% 54.41% 9.52% 23.68% -4.51% 6.68% -2.01% Part B Net Income Growth 1 Sales Growth 2 3 (07/03 (1/4)-1 20.47% 4 5 -6 17 18 19 20 21 22 23 24 25 26 27 28 29 80 31 32 33