262 Francisci Bertelli 



r6y...4S~*'«A(')sin«>-sin2(x— o)==- ■|X'^ /A(')cos(i/H-2jr— 2o) . 



Cum aulem sit 



sin'(x— «)=— ^[cos2(J!:— «)— 1 |, 



secundus lenninus ejusdem facloris erit 



-*-oo ^ 



S i'- A(')co sifcos2(x — o) ^ 



— 2S I'iM'lcosirsm-ix — o)=< 



-00 J \ / ^ -t-oo 



— 2 /^A(')co«/ 



(7)... 2 i^ A(')cosj/cos2(ar — e>) = 2 i-A(')cos(</-i-2x — 2o) ; 



Veruni ex formula (3) , (num. 14), est 

 (7)... 2 i^ AWcosj>cos2 



^ ' —00 



is igilur terminus evadet 



/ ■ -1-00 



V 2 /-A('')cos(/r-*-2a' — ZoA , 

 -1-00 ) -00 ^•^ ^' 



(8)...— 22 i^A.i')cosirsin'-(x—o) =< 



r — 2 i-A(')cosy'- 



Quartus autem terminus , et quinius cum ejusdem sint fot- 

 mae, ac termini aequatlonum (2), (3), vertentur in 



-Hoo /</AC')\ . 



^^^" ^ ^-^00 /^A(')\ 



00 /dMi)\ 



00 \ da I 



+00 /f/A(')\ 



-00 \ da j 



-4-00 /dA{'}\ 



, -1-00 /dA{')\ 

 -00 \ a / 



-1-00 /rfA('A 

 -^^-ooH'rf^)'^'^'^''"^''""^"^- 



Sextus denique et postremus terminus factoris quadrati e ob 

 aequalitatem hanc 



cos*(x— tf)=i[cos2(x— »)+.1 j 



fiet 



