By studying historical data we can know the compounded growth rate of an investment from the inception date. For example if we know that an investment has grown at the rate of 6% in the past and if we expect similar growth in the future also, We can plot this graph to understand whether the current price is underpriced or overpriced as per projected return.
In this graph, it takes the initial close price as a principle and rate from the input and calculates the compound amount at each interval.