3. Planet 1 and 2 are in coplanar circular orbits about the sun, with average distances a and a2 respectively where a2 > a. a) Give an expression for the period of revolution about the sun for each planet and indicate the units in any formulae. b) Derive a general equation expressing the time interval to between successive oppositions of planet 2 as seen from planet 1, assuming that both planets are in coplanar circular orbits and P > P. (Recall that from one opposition to the next, the inner planet will make exactly one more revolution about the Sun than the outer planet.) c) Apply your expression to find the approximate intervals between. oppositions of Mars as seen from the Earth d) Now apply your expression to find the approximate intervals between oppositions of Jupiter as seen from Mars.