I need to find the derivative of a function for a given value of the argument Can smb help?

F(x) = ln cos x; F'(-pi/3)

1 Answer
Jun 11, 2018

F'(-pi/3) = sqrt3

Explanation:

Using the chain rule:

(dF)/dx = 1/cosx d/dx cosx = -sinx/cosx = -tanx

So:

(dF)/dx|_(x=-pi/3) = -tan(-pi/3) = sqrt3