8 
dA m 
fB m + i=z r —mA m , 
dr 
unde, si in hac postrema m mutetur in m — 2, per 
nationem ipsius B m . 1 formula (4) procîit. 
(9) 
elimi- 
Statuamus similiter 
f'{r Cos x) 'zzz C -j- 2Cj Cosx -f- 2 C 2 Cos 2# -j- 2 C 3 Cos 3# -j~ etc ‘> 
unde perspicuum fit, coeificientes , littera C designatos, 
eodem modo ex B pendere, quo E ex A pendent: quam- 
obrem, si in aequationibus (8) et (9) B mutetur in C et 
A in #, obtinebitur 
dBn 
r Cm-! = r 
^ m + -1 
dr 
dB m 
dr 
— m B m . 
Ex hac postrema aequatione, mutando m in m . 
colligimus 
C m = 
dBm.! m—l 
dr r 
B m - x 
atque, cum sit ex æquatione (8) 
-D ■ m 
-°/72-i — — ; — **m J 
dr r 
unde per differentiationem obtinetur 
dB m . x d 2 A, 
m 
dr 
dr 2 
d" — 
m dA, 
m 
m 
r A 
r ar 
r ■ 
m 
