1. The problem statement, all variables and given/known data The question is: "Derive the relationship between a planet's synodic period and its sidereal period (Eq. 1.1). Consider both inferior and superior planets." Figure 1.7 and Equation 1.1 are attached. 2. Relevant equations Attached. 3. The attempt at a solution The solution states: "From Fig. 1.7, Earth makes S/P_⊕ orbits about the Sun during the time required for another planet to make S/P orbits. If that other planet is a superior planet then Earth must make one extra trip around the Sun to overtake it, hence S/P_⊕ = S/P + 1. Similarly, for an inferior planet, that planet must make the extra trip, or S/P = S/P_⊕ + 1. Rearrangement gives Eq. (1.1)." I am VERY confused. I found definitions for some things that were confusing me.: (1) The sidereal period is considered to be an object's true orbital period. (2) The synodic period is the time period between two successive astronomical conjunctions of the same celestial objects. (3) Planets closer to the Sun than to Earth are inferior planets. (4) Planets that are farther away from the Sun than Earth are the superior planets. So from that, I feel pretty confident about (3) and (4), think I get (1) but I'm heavily confused about (2). Also, could someone relate (1) and (2) to Figure 1.7 for me please? If I left something out and/or more information is needed, just ask me and I will add whatever more is needed. Any help would be GREATLY appreciated! Thanks in advance!