5 8 AEROPLANE PERFORMANCE CALCULATIONS 



I i I i 1 / W, 



ax = - \ log, w\ = | log, w I = log, (^ 



Ji' 





Again dt = d , from (5) 



- from (7) 



aV'w 



TT, ~ from (I) 



from 



Now one of the standard cases of the differential calculus 

 gives us 



+ y 







Now let j = ^/W ....... O) 



and 



f * = - 



J ^ V 



-'-- "'"- - ""I?)] 



Now there is a trigonometrical formula 



