multiple formula variations

going through some futures info and noticing multiple ways to calculate index future prices based on present values of the dividends or using the dollar amount to derive dividend yield, pages 116-117 derivatives book. formula that defines yield as g (not sure what greek symbol that they’re using), is a bit crazy. this not a great question, but anyone know if we’re ok being able to calcluate an index futures in this instance through the standard method of subtracting PV or FV of dividends then multiplying by risk free rate adjusted for time period, as opposed to knowing several methods to arrive at the same value? thanks, john