DIFFERENTIATION 88 



(1) If V -8Vx 



then y = 8or then a - 8 and n - - 



I 



d# 2 



VaJ 



(2) If 2/=T% 



12 "~ 



r 



a* 



T 



then t/ = r = I2x " a = 12 and n = - 



3,2.5 



53. If y = a. This represents a line drawn parallel to the axis 

 of x, at a distance a from it. Since it is parallel to the axis of x, 

 the angle 6 = 0, and tan 6 = 0, 



du 

 and so the slope, or =tan 6=0 



Thus if y=a -^ = 



54. y = (?* where a is a constant and e is the base of Napierian 

 logarithms. 



If y=e?* 



then y+By= ^ x+&x} = 0* x 



-1) 



Making &r infinitely small, 

 then 



OB 



