i:8r DE vmVLlS CTUNDRORVAl 



Ex fimiUmdine triangulomm PMN et BCD orictur ana- 

 logiii haec : B C (Z^) : C D (f) ri P M ( J ) : M N ( ? ) ■, ergo 

 area PMN^ quae el\—-^, duda in elcmcntum Pp- 

 vcl «'.v, exliibebit elementum femi-.ngulae per axem. 

 lecflae, qunm exprimo pcr (fu—--jj~\, cuius Integrale- 

 ita fumendum, vt hOiOj—o^u euanefcat. 



§. 6. In iisdem Figuris eruitur quoque clementum) 

 fuperficici vtriusque fcmi-vngularis. Nempe ex prio- 

 £^.3. ribus iiabetiur M/«— V («'.v ^ -f-^j' ^ ) , adeoquc pro 

 femi-vngulis per ordinatam N M x Mm ~ ""^ ^\ ~^^-'' ^— 

 ^S, quae formula erit pro determinandis fuperficicbus 

 femi-vngularum pcr ordinatas cfectirum; eius vcroln- 

 tegralc ita fumcndum, vt fidta .vzr o , liat S=r o. Pro. 

 fuperlicicbus vero femi-vngularum per axem ficlis , crit 

 MmxMN = ?-2^^^-^z:^^.f, cuius Intcgrale ita fu- 

 mendurn , . vt fida j :=^ o , fiat .f zz: o . . 



Fig 4-. 



^, 7. Accedam nunc his pracmiffis propius ad cxcu-< 

 ticndai; . variorum Cylindrorum Vngulas, et primo qui- 

 dcm ad... eas , quac ongincm fuam dclx:nt Cylindro com- 

 TnbKia ni. ixiiiui^ fcii Circulari.. Sit igi^tur fcmi-cylindrus Circu- 

 ^^'-^' laris AF,.atque. efecctur. ex eo Vngula dimidia EOD , 

 pofitis B P - .V , P M — j' , B A :3. ^ , B O — l^ , C A ra- 

 dio circuii' "?', crit AP~<7 — .v, atque ?K — 2r — a. 

 -+-.V, vnde, obPM = — APnPK, crit j'~V(2ar- 



a~ -+- 2.-a,v~-2r x — x ,-')■, vndc fi t — ^j x dx — x <ix 

 y_!^nj^y^ (1? ^ 2;^ .V — 2 r .V — .V " ) =r ( xdx — a- r. dx ) 



y,( 2^r-«,- --H za x-^r x-x~')-\- a-r.j.dx. . Quac. 



forrau.- 



