<Dl> <Dd> (1 − ε) tan 2 ⁡ θ 2 = (1 + ε) tan 2 ⁡ E 2 (\ displaystyle (1 - \ varepsilon) \ tan ^ (2) (\ frac (\ theta) (2)) = (1 + \ varepsilon) \ tan ^ (2) (\ frac (E) (2))) </Dd> </Dl> <Dd> (1 − ε) tan 2 ⁡ θ 2 = (1 + ε) tan 2 ⁡ E 2 (\ displaystyle (1 - \ varepsilon) \ tan ^ (2) (\ frac (\ theta) (2)) = (1 + \ varepsilon) \ tan ^ (2) (\ frac (E) (2))) </Dd> <Dd> 4 . Compute the heliocentric distance <Dl> <Dd> r = a (1 − ε cos ⁡ E). (\ displaystyle r = a (1 - \ varepsilon \ cos E).) </Dd> </Dl> </Dd> <Dl> <Dd> r = a (1 − ε cos ⁡ E). (\ displaystyle r = a (1 - \ varepsilon \ cos E).) </Dd> </Dl>

What is the name of the 3rd law of motion