340 GENERALIZED COORDINATES 



Now since, as in equation (158), 



we must have 



Sx = x' x 



neglecting small quantities of the second order. 

 Thus 



where ^ 2 , , depend on the configuration of the system, 

 and therefore are functions of lf 2 , ., 6 n only. 

 Equation (173) now becomes 



Just as in 270 we found that 







SLdt 

 could be transformed into 



so the first term of equation (174) can now be transformed into 



Substituting this, the equation becomes 



