The question of concern is the following. Sketch the subset $S$ where $S={z: \frac{-\pi}{4}\le Arg(z-(-2+i)) \le \frac{3\pi}{4}} $. The provided answer is the following.
This is where I am confused. Why is there a dotted boundary line here? Would the sketch not be equivalent to first sketching $\frac{-\pi}{4} \le Arg(z)\le \frac{3\pi}{4}$ which would not have such boundary line, and then translating the origin up to the point $-2+i$. Thank you in advance.
