(90) 



cnm ante efTe debiierat conftans , nunc requiritiir vt certac 

 cuipiam fundioni datae aitirudinis Y Z ~ ?: acquetur , quae 

 ergo fundio fi ftatuatur n: Z , folutio problematis hac conti- 

 nebitur aequatione : z -]/ (i -\- p p ~\- q q) — Z. 



§. 30. Ex hac igitur acquatione ftatim deducimus 

 pp^qqziz^l^i vnde fi ponamus ;> =: '-^ /(Z* — s') , 



iiet q — ■^■!^^ -^ (Z" — z"). Quare cum effe debeat dzzzipdx 



-\- q dj ^ fada fubftitutione habebimus ; > 



dz — lli^l-iLll' {d X col. (p-hdj fin. <p) , 



vnde colligitur 



-^^l^— = 5 .r cof. Cb -I- aj fin. (!) , 



Tbi cum membrum finiftrum per fe fit integrabiJe , quippc 

 vnicam variabilem ;5 inuoluens , etiam mcmbrum dextrum per 

 fe integrabiic reddcndum eft; vnde fi diffcrentiah*a ad elemcn- 

 tum d(P reducamus , nancifcemur, vt ante, hanc aequationem: 



/ -^/-^-^ = X cof. (p H- j fiu. (p-^fd(p (.V fin. (J) —j cof (p). 



§. 31. Ncceffe igitur eft, vt formula xfm.(p—jcor.(^ 

 fit fundio vnius variabiHs (p , quae ponatur rr — O vt fit 

 y cof Cp — A- fin. (pzziO. Deinde quia intcgrale / — |,^^, vt 

 cognitum fpediare iicet, eius loco fcribamus litreram 1', vt fit 

 v~/"_^i_? , ct acquatio noftra hanc induct formam: 



'v=zx cof. (p-\-j fin. Cp — /O 5 (p , vnde fit 



X cof. (J) -}-r fin. (pzrzv -+-/0 5 Cj) , 

 ex qua acquationc, cum illa: j cof. Cp — x fm. (p =z O combi- 

 nata, dcducnntur fcquentcs valores : 



X zzz v cof. Cp-H- cof (pfOd<P — O fin. (p ct 



j zzz-v fin. Cp -f- fin. Cp/a) D Cp -1- cD cof (p , 



ita 



