SEMAINE D'ÉTUDE SUR LE ROLE DE L ANALYSE ECONOMETRIOUE ETc. 067 
whence 
538-5) 
| 
[t is interesting to note that for 
Zz, 
y 
ye, 
3 
the value obtained from this approximative formulation does 
not differ from the exact value by more than 18%. 
Study of a Particular Case 
539. It is interesting to examine the variations of the essen- 
tial functions in the particular case in which 
(530-1) 
w 
~ 
with 
(530-2) 
,.5 for u- 
| Allais - pag. 27