## Precalculus (6th Edition) Blitzer

$y=cot(\frac{3}{2}x)$
Step 1. This graph is similar to the cotangent function $y=cot(kx)$ Step 2. From the given period $\frac{2\pi}{3}$, we have $\frac{\pi}{k}=\frac{2\pi}{3}$, thus $k=\frac{3}{2}$ Step 3. The function is $y=cot(\frac{3}{2}x)$