Question

Integrate:

${\int }_0^{2\pi }|\cos x|dx$ is equal to

• A. $0$
• B. $4$
• C. $-4$
• D. $2$

Answer 1

The correct option is B $4$

Graph of $\left|\cos x\right|$

$\Rightarrow {\int }_0^{2x}\left|\cos x\right|dx=4{\int }_0^{\pi /2}\cos xdx$

$=4x{\left[\sin x\right]}_0^{\pi /2}$

$=4.$

Hence, the answer is $4.$