(47) 



Euolutio 

 formiilarum pro cof. «cp inuentarum, per logarithmos 



et differentiationem. 



§. 35. Cum rupra inuenerimus 



cof. 2 (p — 2 cof. Q f -4- Cp) cof. (s ^ — 0) , 



erit fumtis logarithmis 



/ cof. 2 zr: / 2 + / cof G ^ -h 0) -I- / cof. ({ f — 0), 



quae aequatio quia vera eft pro angulo quocunque (P, fpede- 



tur Cf) vt quantitas variabilis, ac dilfereniiatio nobis praebebit 



hanc aequationem : 



aacpfin. 2(|)_ d(Pfin.a?-h(^) d f\n. (l^ — (p) 



cof 2 <p coi; a f -H Cp) cof. G ^ — Cp) 



quae per — 5 Cp diuifa per tangentes dabit 



2 tang. 2 Cp =: tang. (4.5° h- Cp) — tang. (^^° — (p) , 



id quod exemplo illuftrafle iuuabit. Sit igitur C|)— 17°, 30% 

 eritque 



2 tang. 35*^ = tang. (62°, 30^ — tang. (27°, 30''). 



Eft vero ex tabnlis 



tang. 62%3o'' — i, 9209821 

 rang. 27,30 =0,5205(571 



2 tang. 35° =: i, 4004150 



Oiflferentia 



I, 4004150 



§. 35. Deinde quia fupra inuenimus 

 cof. 3 Cp r= 4 cof. (60° H- CP) cof. {60° — Cp) cof. Cp, 

 erit pcr logarithmos 



/ cof. 3 Cp rr / 4 -+- / cof. Cp -t- ; cof. (5o° -+- Cp) / cof. (do"— Cp) . 



Hinc 



