Dcmonn.ratio. 



Diita fit aequatio bafcos nnturnm cxprlmcns inter coordina* 

 tfls M R — .V, R Q — V, et planum O M tn lccctur a plano ^ q n 

 in linea N u. Duciis rciftis O R, O Q, plano N q u occurrcntihus 

 in pundis r, </, crit N ;; lincac M ;/;, ct r q lineae R Q parallcla. 

 Hinc angurus coordinatarum N;v/rMRQ; MR:N;-=OR:Or 

 — R Q : ;• </. Quarc fi ponatur Nr — r, r q :r=: u , erit 

 Jr izz ^ r , j' zz: ii-? // ; ac fi C P fit fcmiaxis coniu2atus ~A, 

 M C =: ^, atquc planum O C P a plnno N q n fccctur in linea 

 f p, parircr crit M C P — N r/>, ct M C : C ;« =: N <: : c », er- 

 go f cllipfcos N ^ ;/ ccntrum , <2 — ?— N f , b — — c p^ idco- 

 quc a : If zn K c : c p. Quibus omnibus valoribus in acquatio- 

 ne data pro bafc fubllitutis, ob "" rationcm coulhintcm, rclul- 

 tabit acquatio intcr / ct // propofitac pcrfcdc fimilis. 



Noftro cafu, ob C M r ^, C P = /», eft.r.r^^Cfl^— a-a-), 



pofito nempc C R ~ .v. Quocirca fi in cllipfc Nqn dicatur 

 N <• n: a, c p = (l, c r — t^ r q — u., crit 



a a ^ ' m m 



§. 7. Scorfim nunc contcmplcmur coniim cllipticnm 

 Tab. 1. ^ ^^ '" 1 ciiius cum plano tabuiac intcrfce^tio fit curua A Q a. 

 Fig. 4- l'cr cius pundum quodpinm O ponatur planum N Q;/ bafi 

 coni M ;;/ parallcium , critquc N Q ;; cliipfis bafi fimiiis. Pcr 

 axcm bafcos priucipalcm M ;// ct ^criiccm O ducatur planum 

 M O ;;/, quod crit ad utrumcjuc plauum N Q ;; ct AQ^ nor- 

 ir.alc , quia (§. 5. lig. 2. ; P C M — 90' =: P C O , ct O C 

 ad hori/ontcm pcrpcndicularis. Ad comn.uncm intcrrcifiioncm 

 A /7 planorum A Q ^ ct M O ;;/ agarur normalisQ*/, quac pa- 

 riicr cric normalis ad planum M O ;;/, idcoquc Qr/N— po« 



Qua- 



