Methodus inveniendi lineas curvas

MAX. ET MIN. RELATIVA. 235 incrementum $p\pi \cdot P''dx$; quæ omnia, si cui libuerit calculum eo modo quo in Cap. præc. Propos. 3 §. 22 usi sumus persequi, sa- tisfient manifesta ac perspicua. Eodem igitur porro modo ex- pressio $B$, cujus valorem differentialem ex unica particula $n\nu$ oriundum posuimus $= n\nu \cdot Qdx$, ex tribus particulis $n\nu$, $o\omega$ & $p\pi$ incrementum accipiet $= n\nu \cdot Qdx + o\omega \cdot Q'dx + p\pi \cdot Q''dx$. Tertio expressio $C$ ex his tribus particulis augmentum capiet hoc $n\nu \cdot Rdx + o\omega \cdot R'dx + p\pi \cdot R''dx$. Singula jam hæc tria incre- menta seorsim nihilo æqualia poni oportet, ut omnibus condi- tionibus præscriptis satisfiat; unde tres sequentes æquationes orientur, facta divisione per $dx$, $0 = n\nu \cdot P + o\omega \cdot P' + p\pi \cdot P''$ $0 = n\nu \cdot Q + o\omega \cdot [TRUNCATED]