Answer
$y=-4sin(2x)$
Work Step by Step
1. Based on the given graph, we can initially identify that it resembles a graph of negative sine.
2. We can determine the amplitude $|A|=4$, period $p=\pi$, passing $(\frac{\pi}{4},4)$.
3. Write a model as $y=-4sin(\omega x)$
4. We have $\frac{2\pi}{\omega}=\pi$, thus $\omega=2$
5. The equation is $y=-4sin(2x)$
