In the following sections, we show that those two force laws produce stable, exactly closed orbits (a sufficient condition)
ɪnðə fˈɑːloʊɪŋ sˈɛkʃənz, wiː ʃˈoʊ ðæt ðoʊz tˈuː fˈoːɹs lˈɔːz pɹədˈuːs stˈeɪbəl, ɛɡzˈæktli klˈoʊzd ˈɔːɹbɪts ɐ səfˈɪʃənt kəndˈɪʃən