fˈɪks sˌʌm ˈɛlɪmənt ʌv , ænd dᵻfˈaɪn baɪ hˈɪɹ ɪz ˌɛni dˈɪfɚɹˌɛnʃɪəbəl kˈɜːv ɪn ɚɹˈɪdʒᵻnˌeɪɾɪŋ æt ænd tˈɜːmᵻnˌeɪɾɪŋ æt .
Fix some element  of , and define  byHere  is any (differentiable) curve in  originating at  and terminating at .