Page 183 - Calculus Demystified

Transcendental Functions
CHAPTER 6
170

Fig. 6.10

Fig. 6.11

6.4.3 LOGARITHMIC DIFFERENTIATION

We next show how to use the logarithm as an aid to differentiation. The key idea is
that if F is a function taking positive values then we can exploit the formula
F

[ln F] = . (∗)
F
EXAMPLE 6.28
Calculate the derivative of the function
(sin x)
F(x) = (cos x) , 0 <x <π.