= Ci50 == 



qihiriim hin.ic priorcs motiim progrcniiium puiKfli C dctcrmi- 

 nanf, tcrtia \cro motum gyr:Uorium. Qu;irc cum iplu tculio 

 ctiiimnunc fit incognita, cain ante omnia e calculo clidi opor- 

 tct , id quod commodiilimc ficri potcll. Quia enim cx terua 

 cft '-^— zz: LLi^ , hic valor in prioribus fubllitutiib nobis pr.ic- 

 bcbit hns duas acquationes fimplicinimas : 

 I. ddx-hcf)d(p cof. ^ =: o 

 11. ddy -{- cddi^fni.C =: o 

 cx quibus iam totam folutioncm dcriuarl oportct. 



§. 7. Commode autcm has duas acquationcs ad duas 

 quantitates variabilcs z ct rcduccrc liccbiti cum cnim inuc- 

 nerimus DCj) — — — D ^, crit DDCpzz:^^'' — dd&i tum vcro, 



cum Ht 



.Y ~ 2 cof ^ — A Hn. ct 



j' rr 3 fin. ^ -f- <7 col". , crit 



d X = dz cof ^ — c r^) t> fin. ^ — n ?) (> cof. i^ ; 



dy —dzC\n.6-hzd& cof. — a ^ ^ fin. e ; 



liincquc porro differentiando 



ddx = d?)zco(.^ — 2dzdn\n.^—zddn\nJ 



— addi} cof 0-{-adi' i\n.^ — zdi* col". t» ; 

 ddY=^^^z{in.6-{-zdz?)6co(.6-{-zdd&coC.9 



— a^^Ofin.Q — ad&^coC.O — zdD^nn.d; 



quibus valoribus rubllitutis binac noHrac acquationcs inducnt 

 fcqucntcm forn->am : 



(^ — zd$'-\-(i-{--^)(d?z—add6)co(.9 



~(zdcf$-{-zdzdO — a?)0')fin.& = 



■ (zddH-idzdO — adi^jQn.O =10. 



§. 8. 



