344 Mr. Lubbock on the Variation of 



(cf~r) = i" B cos (i" n t + j" mnt + I" nt ). 



rru . d 



Inese terms give in -j 



I i 



d e d c) a n dco dc an 9 



and therefore 



* \ / tMl (** 



dc/V aw V"^ 



dw 



and hence the following terms : 

 i' CB A sin (i 1 n t -f / m n t + I 1 n t} 



cos (if 1 nt +j"mnt + I" n t) 

 (i" +fm + l"}n ~ 



H -- - sin (i 1 n t + j' m n t + /' n t} 







cos (i" nt i n t +j"mntjmnt-\- I" tit In t) 

 (i" i +j" m jm + i" I) n 



i -- - - sin (i' nt +j'm?it + V nt) 



z \ 



cos (i" nt+ int +j" mnt +jmnt + V nt + Int) 

 (i" + i +j"m +jm + I" + l)n 



i" CBAcos (i" n +j" mnt + I" n t} 



sin (i' nt -f j 1 m n t 



cos(i"nt +fmnt + l"nt) 







sin ^ 7 fit i nt +j' mnt jm n t + I' n t V n t) 

 (i 1 i +j'm jm + I 1 I) n 



cos (i" n t +j" mnt + 1" n t) 



sin (i 1 nt + int +j' mnt +j mnt + I' n t -f Inf) 

 (i 1 + i +j'm +jm + I' + I) n 



The terms multiplied by C B A, which arise from the constant 

 portion of [>, o>], have already been considered, the rest form four 



