Question

over which interval is the graph of y = cos(x) strictly increasing?
0 < x < \frac{\pi}{2}
0 < x < \pi
\frac{\pi}{2} < x < \frac{3\pi}{2}
\pi < x < 2\pi

Explanation:

Step1: Recall cosine - function property

The general form of the increasing - interval of the cosine function $y = \cos(x)$ is $(2k\pi+\pi,2k\pi + 2\pi),k\in\mathbb{Z}$. When $k = 0$, the increasing interval is $(\pi,2\pi)$.

Answer:

D. $\pi