(i)[5]
Demonstrate that $\frac{dy}{dx} = 4 \cos^2 x - \sec^2 x - 2$.
(ii)[4]
Hence determine the $x$-coordinate of $M$, giving your answer correct to $2$ decimal places.
Mathematics 9709 · AS & A Level · Differentiation
Differentiation — practice question
The diagram illustrates the curve $y = \tan x \cos 2x$, for $0 \leq x < \frac{1}{2}\pi$, together with its maximum point $M$.