sˈɪns ɪz pˈæθˌɪndᵻpˈɛndənt,  ɪz ˈoʊpən, ænd ɪz ɐpɹˈoʊtʃɪŋ zˈiəɹoʊ, wiː mˈeɪ ɐsˈuːm ðæt ðɪs pˈæθ ɪz ɐ stɹˈeɪt lˈaɪn, ænd pˈæɹəmˌɛtɹaɪz ɪɾ æz fɔːɹ .
Since  is path-independent,  is open, and  is approaching zero, we may assume that this path is a straight line, and parametrize it as  for .