QUICKEST DESCENT. 15 



np -f my . f-LAP 



/ I »■ ^ -r Mi y . 



p 



Now N - ; .-. P = fluent N i + 



Correction ; and therefore 



, z -I- VP 



^.nuentof> ^ ^^tlL,^ -^^^'^ ..i[- 



i_. fluent 



4 2-7- . fluent 



f (na:-m Vx»+yO' j 



+ Cor. ; or, by substitution, 



-— — :—-; r-- — -— z= fluent 



