You appear to be on a device with a "narrow" screen width (i.e. you are probably on a mobile phone). Due to the nature of the mathematics on this site it is best views in landscape mode. If your device is not in landscape mode many of the equations will run off the side of your device (should be able to scroll to see them) and some of the menu items will be cut off due to the narrow screen width.
Section 3.5 : Derivatives of Trig Functions
4. Differentiate \(f\left( x \right) = 2\cos \left( x \right) - 6\sec \left( x \right) + 3\) .Show Solution
Not much to do here other than take the derivative.\[f'\left( x \right) = - 2\sin \left( x \right) - 6\sec \left( x \right)\tan \left( x \right)\]