1. The problem statement, all variables and given/known data Let's say you want to find the minimum and maximum observed frequencies of light observed on Earth from the sun, when considering the Earth's motion around the sun. How would you go about doing this if you assume Earth takes time X to complete a revolution around radius R? 2. Relevant equations Well, this is an example of Doppler Shift I assume, so frequency observed = Vphase / [ (Vsource + Vphase)(frequency node)] where Vphase is the speed of light. 3. The attempt at a solution So frequency observed is easy enough to set up, but how I'm not sure how to incorporate the parameters X and R to get the minimum and maximum frequencies.