Simili modo pcr formulam /Qds erit 



/P^x-^;/Q^x et /Kdszzz^l^-^/Clds. 



Porro vero per /R d s fiet 



/P^j=:^^/R^i ct fQ_dszz'^yjRds. 



§. 8. Hinc igitur tcnfionem T pcr quamlbct ha- 

 rnm formularnm integralium, cxciufis binis reliquis, ex- 

 primere poterimus. Primo enim erit per f)rmulam f? d s: 



Tzz-^''f?ds-^y;r?ds-p^f?ds-~i^fPds, 



propter d x" -\- dy- ~\~ d z- - d s"-. Rodem modo per for- 

 rrulam/Q^f reperiemus quoquc Tz. — ^^^fQds et per 



foimiilam/R^j-, T — -^^JKds. 



^. 9. Quod fi crgo tcnfioncm T tanquam da'am 

 fpedcrrus, nodrae formulae integrales ita definicntur vt fit 



JVds = -l±^, 



fKds=:-yL2, 



ex qnarum differcntiatione, fi clemontnm ds confians ca- 

 piamus, ipfas vires foUicitantes ?df, Q_d s ct Kds, ex 

 tcnfionc T clefinirc liccbit hoc mt)do: 



Td sz:z~ 



dTdx — r i d X . 



d s 



Qj, dTd7 — T < d 7 . 

 ds = - ^^ , 



di » 



inuis fore: 



Vd.x 



R ^j__Ud^-Ti<<^. 

 atquc hinc porio concludimus fore: 



