Equation of Circle in Complex Plane/Examples/1 less than mod (z + i) not greater than 2

Example of Use of Equation of Circle in Complex Plane
The inequality:
 * $1 < \cmod {z + i} \le 2$

describes the inside of the annulus whose center is at $-i$, whose inner radius is $1$ and whose outer radius is $2$.

The annulus does not include its inner boundary, but does include its outer boundary.


 * Equation of Annulus in Complex Plane-Examples-1 to (z + i) to 2.png