Mathematics

Problem

Let

F(x)=\sec x - x

for

0<x<\dfrac{\pi}{2}

. The derivative

F'(x)

equals

0

at a single point in this interval. Which of the following values is closest to that

x

-coordinate? a)

\dfrac{\pi}{4}

\dfrac{2\pi}{9}

\dfrac{\pi}{8}

\dfrac{\pi}{6}