== (PO) === 



dem manet. Iniientis autem pro quouis cafu valoribus ifta- 

 rum formularum j cof. Cf) H- x fin. (J) et j fin. Cp — a- cof. (p, in- 

 de fiicile ipfas coordinatas x et j definire licet. Iftae autem 

 formulae in figura lineas fatis memorabiles defignant. Si enim 

 ex pundis a et x in normalem sr ducantur perpendicula ap 

 et xz^ cx a: vero in ap perpendiculum xq^ ex triangulo xsz, 

 ob angulum s xzz=:^^ erit s z ~y fin. (}) et .v s ~y cof Cpj 

 deinde vero ex triangulo axq fiet «^ = A-fin.Cpet jr^rxcof.Cp, 

 ex quibus coUigitur reda ^p rjcof Cp-i-jrfin.Cj); at vero reda 

 s p — s z — X q — j fin. C|) — jf cof. Cp. Quare fi ad curuam in 

 s ducamus tangentem st, in eamque ex a perpendiculum de- 

 mittamus at, ac vocemus at—p et st — t^ eric 



p —y fin. (p — X cof Cp et 



f zr: j cof. 4^ -}- X fin. Cp. 

 Inuentis autem his duabus quantitatibus ^ et f , inde vicifllm criC 



A-^/fin. Cp — /) cof Cp et 



y z=zp fin. 4) -f- t cof Cp. 



§. 16. Quodfi ergo praeter radium ofculi r et arcum 

 curuae s loco coordinatarum x tt y iftas binas quantitates I 

 et /) in calculum introducamus , pro curua quaefita a s fequen- 

 tes habebimus formulas fatis concinnas: 

 I. r = f f'^ fin. (y -I- >i Cp). 

 II. s — ^^ e^'^ [^ fin. {y-\-y\<^) — y\ cof (y — >i Cj))] . 



III. s — ~ '- -/^[^fin.(y-4-v]Cp)-(>]+i)cof(y-»-vi(J))] 



IV. p — " ^^^[^cof(y-+--viCl))-+-(>]-t-i)fin.(y-HviCp)] 



* a(aa-(-2a/m.UJ-)-i) 



iti ^^^[<cof (y-+->)C{))-H(>i-i) fin. (y-H>)(|))]. 



i(aa — 2ajm.cjj-f-i) 



Hinc igitur ipfae coordinatae .v et jk ita definientur, vt fit 

 A-rr^fin. Cp — /> cof Cp et 

 y—pa^.<^-\~t cof Cp , toc- 



